Show inline previews for LSP document colors (#32816)

https://github.com/user-attachments/assets/ad0fa304-e4fb-4598-877d-c02141f35d6f

Closes https://github.com/zed-industries/zed/issues/4678

Also adds the code to support `textDocument/colorPresentation`
counterpart that serves as a resolve mechanism for the document colors.
The resolve itself is not run though, and the editor does not
accommodate color presentations in the editor yet — until a well
described use case is provided.

Use `lsp_document_colors` editor settings to alter the presentation and
turn the feature off.

Release Notes:

- Start showing inline previews for LSP document colors

crates/editor/src/editor_tests.rs

@@ -22,8 +22,8 @@ use indoc::indoc;
 use language::{
     BracketPairConfig,
     Capability::ReadWrite,
-    FakeLspAdapter, LanguageConfig, LanguageConfigOverride, LanguageMatcher, LanguageName,
-    Override, Point,
+    DiagnosticSourceKind, FakeLspAdapter, LanguageConfig, LanguageConfigOverride, LanguageMatcher,
+    LanguageName, Override, Point,
     language_settings::{
         AllLanguageSettings, AllLanguageSettingsContent, CompletionSettings,
         LanguageSettingsContent, LspInsertMode, PrettierSettings,