Consistent highlight on derives' qualIds

fix: #239

vscode-scala-syntax couldn't provide consistent highlights for
`C` and `D` in `derives C, D`.

Consider we have the following code

```scala
enum A extends B derives C, D
```

Previously,
`B` and `C` have the following TextMate Scopes

```
entity.other.inherited-class.scala
source.scala
```

while `D` has

```
entity.name.class
source.scala
```

because it had accepted only one qualId after `derived`
https://github.com/scala/vscode-scala-syntax/blob/0b2b1e8829254f0d190e723d3a49874cb7d135c0/src/typescript/Scala.tmLanguage.ts#L1156
even though Scala3 syntax allows us to put multiple qualIds.
Therefore, the first one will have `entity.other.inherited-class.scala`,
but the following qualIds won't be named as
`entity.other.inherited-class.scala`. Instead, falllback to
`entity.name.class` based on it's name (upper camel).

This commit makes it provide consistent highlight for each qualId after
`derives` keyword.
Now, both `C` and `D` will have `entity.name.class` instead of
`entity.other.inherited-class.scala`.

It would be ideal to put `entity.other.inherited-class.scala` to both `C` and `D`,
but it looks like impossible with TextMate grammer.
Because, according to the [syntax](https://dotty.epfl.ch/docs/reference/contextual/derivation.html#syntax)
(see the syntax spec for Scala3 here https://docs.scala-lang.org/scala3/reference/syntax.html)
we can't tell where's the end of `derives` clause.

In the complete program, we can tell `{` or `:` is the end of `derives`
clause, but it messes up if the program is incomplete like

```scala
enum A extends B derives C, D
```

where there's no `:` or `{`.

Just give up providing `entity.other.inherited-class.scala` and
put `entity.name.class` based on their name (upper camel).

Author: tanishiking

src/typescript/Scala.tmLanguage.ts

@@ -241,6 +241,9 @@ export const scalaTmLanguage: TmLanguage = {
         {
           include: '#inheritance'
         },
+        {
+          include: '#derives'
+        },
         {
           include: '#extension'
         },
@@ -1153,7 +1156,7 @@ export const scalaTmLanguage: TmLanguage = {
     inheritance: {
       patterns: [
         {
-          match: `\\b(extends|with|derives)\\b\\s*(${idUpper}|${backQuotedId}|(?=\\([^\\)]+=>)|(?=${plainid})|(?="))?`,
+          match: `\\b(extends|with)\\b\\s*(${idUpper}|${backQuotedId}|(?=\\([^\\)]+=>)|(?=${plainid})|(?="))?`,
           captures: {
             '1': {
               name: 'keyword.declaration.scala'
@@ -1165,6 +1168,10 @@ export const scalaTmLanguage: TmLanguage = {
         }
       ]
     },
+    derives: {
+      match: 'derives',
+      name: 'keyword.declaration.scala'
+    },
     extension: {
       patterns: [
         {