Add missing function return type in filters.md (#1791)

* Update function return type in filters.md

* docs: various fixes in filters.md

* Update filters.md

---------

Co-authored-by: Kévin Dunglas <kevin@dunglas.fr>

Author: leonardsimonse

core/filters.md

@@ -1,7 +1,7 @@
 # Filters
 
 API Platform provides a generic system to apply filters and sort criteria on collections.
-Useful filters for Doctrine ORM, MongoDB ODM and ElasticSearch are provided with the library.
+Useful filters for Doctrine ORM, MongoDB ODM, and ElasticSearch are provided with the library.
 
 You can also create custom filters that fit your specific needs.
 You can also add filtering support to your custom [state providers](state-providers.md) by implementing interfaces provided
@@ -23,7 +23,7 @@ to a Resource in two ways:
 
 1. Through the resource declaration, as the `filters` attribute.
 
-   For example having a filter service declaration in `services.yaml`:
+   For example, having a filter service declaration in `services.yaml`:
 
     ```yaml
     # api/config/services.yaml
@@ -254,15 +254,15 @@ The above URLs will return all offers for the product having the following IRI a
 
 ### Date Filter
 
-The date filter allows to filter a collection by date intervals.
+The date filter allows filtering a collection by date intervals.
 
 Syntax: `?property[<after|before|strictly_after|strictly_before>]=value`
 
 The value can take any date format supported by the [`\DateTime` constructor](https://www.php.net/manual/en/datetime.construct.php).
 
 The `after` and `before` filters will filter including the value whereas `strictly_after` and `strictly_before` will filter excluding the value.
 
-Like others filters, the date filter must be explicitly enabled:
+Like other filters, the date filter must be explicitly enabled:
 
 [codeSelector]
 
@@ -533,7 +533,7 @@ You can filter offers by joining two values, for example: `/offers?price[gt]=12.
 
 ### Exists Filter
 
-The exists filter allows you to select items based on a nullable field value.
+The "exists" filter allows you to select items based on a nullable field value.
 It will also check the emptiness of a collection association.
 
 Syntax: `?exists[property]=<true|false|1|0>`
@@ -582,7 +582,7 @@ App\Entity\Offer:
 
 [/codeSelector]
 
-Given that the collection endpoint is `/offers`, you can filter offers on nullable field with the following query: `/offers?exists[transportFees]=true`.
+Given that the collection endpoint is `/offers`, you can filter offers on the nullable field with the following query: `/offers?exists[transportFees]=true`.
 
 It will return all offers where `transportFees` is not `null`.
 
@@ -600,7 +600,7 @@ api_platform:
 
 ### Order Filter (Sorting)
 
-The order filter allows to sort a collection against the given properties.
+The order filter allows sorting a collection against the given properties.
 
 Syntax: `?order[property]=<asc|desc>`
 
@@ -990,8 +990,8 @@ api_platform:
 
 ### Match Filter
 
-The match filter allows to find resources that [match](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-match-query.html)
-the specified text on full text fields.
+The match filter allows us to find resources that [match](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-match-query.html)
+the specified text on full-text fields.
 
 Syntax: `?property[]=value`
 
@@ -1021,7 +1021,7 @@ Given that the collection endpoint is `/tweets`, you can filter tweets by messag
 
 ### Term Filter
 
-The term filter allows to find resources that contain the exact specified
+The term filter allows us to find resources that contain the exact specified
 [terms](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-term-query.html).
 
 Syntax: `?property[]=value`
@@ -1194,7 +1194,7 @@ final class RegexpFilter extends AbstractFilter
 {
     protected function filterProperty(string $property, $value, QueryBuilder $queryBuilder, QueryNameGeneratorInterface $queryNameGenerator, string $resourceClass, Operation $operation = null, array $context = []): void
     {
-        // otherwise filter is applied to order and page as well
+        // Otherwise filter is applied to order and page as well
         if (
             !$this->isPropertyEnabled($property, $resourceClass) ||
             !$this->isPropertyMapped($property, $resourceClass)
@@ -1260,7 +1260,7 @@ class Offer
 You can now use this filter in the URL like `http://example.com/offers?regexp_email=^[FOO]`. This new filter will also
 appear in OpenAPI and Hydra documentations.
 
-In the previous example, the filter can be applied on any property. You can also apply this filter on a specific property:
+In the previous example, the filter can be applied to any property. You can also apply this filter on a specific property:
 
 ```php
 <?php
@@ -1303,10 +1303,11 @@ class Offer
 ```
 These properties can then be accessed in the custom filter like this:
 ```php
-//App/Filter/CustomAndFilter.php
-protected function filterProperty(string $property, $value, QueryBuilder $queryBuilder, QueryNameGeneratorInterface $queryNameGenerator, string $resourceClass, Operation $operation = null, array $context = []) {  
+// api/src/Filter/CustomAndFilter.php
+
+protected function filterProperty(string $property, $value, QueryBuilder $queryBuilder, QueryNameGeneratorInterface $queryNameGenerator, string $resourceClass, Operation $operation = null, array $context = []): void {  
   $rootAlias = $queryBuilder->getRootAliases()[0];  
-  foreach (array_keys($this->getProperties()) as $prop) { //NOTE: we use array_keys because getProperties() returns a map of property => strategy
+  foreach(array_keys($this->getProperties()) as $prop) { // we use array_keys() because getProperties() returns a map of property => strategy
       if (!$this->isPropertyEnabled($prop, $resourceClass) || !$this->isPropertyMapped($prop, $resourceClass)) {  
           return;  
       }  
@@ -1335,7 +1336,7 @@ services:
         tags: [ 'api_platform.filter' ]
 ```
 
-In the previous example, the filter can be applied on any property. However, thanks to the `AbstractFilter` class,
+In the previous example, the filter can be applied to any property. However, thanks to the `AbstractFilter` class,
 it can also be enabled for some properties:
 
 ```yaml
@@ -1416,7 +1417,7 @@ class AndOperatorFilterExtension implements RequestBodySearchCollectionExtension
 ### Using Doctrine ORM Filters
 
 Doctrine ORM features [a filter system](http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/filters.html) that allows the developer to add SQL to the conditional clauses of queries, regardless of the place where the SQL is generated (e.g. from a DQL query, or by loading associated entities).
-These are applied on collections and items and therefore are incredibly useful.
+These are applied to collections and items and therefore are incredibly useful.
 
 The following information, specific to Doctrine filters in Symfony, is based upon [a great article posted on Michaël Perrin's blog](http://blog.michaelperrin.fr/2014/12/05/doctrine-filters/).
 
@@ -1595,7 +1596,7 @@ On the first property, `name`, it's straightforward. The first attribute argumen
 #[ApiFilter(SearchFilter::class, strategy: 'partial')]
 ```
 
-In the second attribute, we specify `properties` on which the filter should apply. It's necessary here because we don't want to filter `colors` but the `prop` property of the `colors` association.
+In the second attribute, we specify `properties` to which the filter should apply. It's necessary here because we don't want to filter `colors` but the `prop` property of the `colors` association.
 Note that for each given property we specify the strategy:
 
 ```php
@@ -1633,7 +1634,7 @@ class DummyCar
 
 ```
 
-The `BooleanFilter` is applied to every `Boolean` property of the class. Indeed, in each core filter we check the Doctrine type. It's written only by using the filter class:
+The `BooleanFilter` is applied to every `Boolean` property of the class. Indeed, in each core filter, we check the Doctrine type. It's written only by using the filter class:
 
 ```php
 #[ApiFilter(BooleanFilter::class)]