Fix more documentation

Co-authored-by: per1234 <accounts@perglass.com>

Author: silvanocerza

commands/upload/upload.go

@@ -444,7 +444,7 @@ func runProgramAction(pm *packagemanager.PackageManager,
 		}
 	}
 
-	// Get Port properties gathered using Pluggable Discovery
+	// Get Port properties gathered using pluggable discovery
 	uploadProperties.Set("upload.port.address", port.Address)
 	uploadProperties.Set("upload.port.label", port.Label)
 	uploadProperties.Set("upload.port.protocol", port.Protocol)

docs/UPGRADING.md

@@ -57,7 +57,7 @@ message DetectedPort {
 
 The properties previously contained directly in the message are now stored in the `port` property.
 
-These changes are necessary for the Pluggable Discovery.
+These changes are necessary for the pluggable discovery.
 
 ### gRPC interface `BoardListItem` change
 

docs/package_index_json-specification.md

@@ -80,7 +80,7 @@ Each tool describes a binary distribution of a command line tool. A tool can be:
 - a file preprocessor
 - a debugger
 - a program that performs a firmware upgrade
-- a [Pluggable Discovery](pluggable-discovery-specification.md)
+- a [pluggable discovery](pluggable-discovery-specification.md)
 
 basically anything that can run on the user's host PC and do something useful.
 

docs/platform-specification.md

@@ -698,7 +698,7 @@ The tool configuration properties are available globally without the prefix. For
 property can be used as **{cmd.path}** inside the recipe, and the same happens for all the other avrdude configuration
 variables.
 
-#### Pluggable Discovery
+#### Pluggable discovery
 
 Discovery tools are a special kind of tool used to find supported boards. A platform must declare one or more Pluggable
 Discoveries in its [`platform.txt`](#platformtxt). Discoveries can be referenced from other packages, including the
@@ -718,7 +718,7 @@ pluggable_discovery.required.1=VENDOR_ID:DISCOVERY_1_NAME
 ```
 
 A platform that supports only boards connected via serial ports can easily use the `builtin` package's
-`serial-discovery` without creating a custom Pluggable Discovery:
+`serial-discovery` without creating a custom pluggable discovery:
 
 ```
 pluggable_discovery.required=builtin:serial-discovery
@@ -863,9 +863,9 @@ leonardo.upload.network.maximum_size=256
 
 The two above properties will be available as **{upload.serial.maximum_size}** and **{upload.network.maximum_size}**.
 
-#### Properties from Pluggable Discovery
+#### Properties from pluggable discovery
 
-If a platform supports Pluggable Discovery it can also use the port's properties returned by a discovery. For example,
+If a platform supports pluggable discovery it can also use the port's properties returned by a discovery. For example,
 the following port metadata coming from a pluggable discovery:
 
 ```

docs/pluggable-discovery-specification.md

@@ -1,4 +1,4 @@
-Discovery tools are a special kind of tool used to find supported boards, a platform developer can create its own
+Discovery tools are a special kind of tool used to find supported boards, a platform developer can create their own
 following the specification below. These tools must be in the form of executables that can be launched as a subprocess
 using a `platform.txt` command line recipe. They communicate to the parent process via stdin/stdout, accepting commands
 as plain text strings from stdin and sending answers back in JSON format on stdout. Each tool will implement the