Fix inadvertent shadowing of ClientCapabilities subtypes

When removing the LanguageServerProtocol namespace from types in
ClientCapabilities (#1734), some types inadvertently started shadowing
themselves. This lead to client initialization errors when the
initialization request couldn't be decoded:

```
type mismatch at params.capabilities.textDocument.completion.completionItemKind.valueSet.Index 0 : Expected to decode Dictionary<String, Any> but found number instead.
```

Disambiguating these inner types in ClientCapabilities fixes decoding.

Author: plemarquand

Sources/LanguageServerProtocol/SupportTypes/ClientCapabilities.swift

@@ -289,7 +289,7 @@ public struct TextDocumentClientCapabilities: Hashable, Codable, Sendable {
     }
 
     /// Capabilities specific to `CompletionItemKind`.
-    public struct CompletionItemKind: Hashable, Codable, Sendable {
+    public struct CompletionItemKindValueSet: Hashable, Codable, Sendable {
 
       /// The completion kind values that the client can support.
       ///
@@ -310,15 +310,15 @@ public struct TextDocumentClientCapabilities: Hashable, Codable, Sendable {
 
     public var completionItem: CompletionItem? = nil
 
-    public var completionItemKind: CompletionItemKind? = nil
+    public var completionItemKind: CompletionItemKindValueSet? = nil
 
     /// Whether the client supports sending context information in a `textDocument/completion` request.
     public var contextSupport: Bool? = nil
 
     public init(
       dynamicRegistration: Bool? = nil,
       completionItem: CompletionItem? = nil,
-      completionItemKind: CompletionItemKind? = nil,
+      completionItemKind: CompletionItemKindValueSet? = nil,
       contextSupport: Bool? = nil
     ) {
       self.dynamicRegistration = dynamicRegistration
@@ -383,7 +383,7 @@ public struct TextDocumentClientCapabilities: Hashable, Codable, Sendable {
   public struct DocumentSymbol: Hashable, Codable, Sendable {
 
     /// Capabilities specific to `SymbolKind`.
-    public struct SymbolKind: Hashable, Codable, Sendable {
+    public struct SymbolKindValueSet: Hashable, Codable, Sendable {
 
       /// The symbol kind values that the client can support.
       ///
@@ -400,13 +400,13 @@ public struct TextDocumentClientCapabilities: Hashable, Codable, Sendable {
     /// Whether the client supports dynamic registration of this request.
     public var dynamicRegistration: Bool? = nil
 
-    public var symbolKind: SymbolKind? = nil
+    public var symbolKind: SymbolKindValueSet? = nil
 
     public var hierarchicalDocumentSymbolSupport: Bool? = nil
 
     public init(
       dynamicRegistration: Bool? = nil,
-      symbolKind: SymbolKind? = nil,
+      symbolKind: SymbolKindValueSet? = nil,
       hierarchicalDocumentSymbolSupport: Bool? = nil
     ) {
       self.dynamicRegistration = dynamicRegistration