Merge #3817

3817: vscode: highlight syntax tree ro editor r=matklad a=Veetaha

Small textmate grammar declaration to make rust-analyzer syntax tree more easily inspectable:
Btw, if we change the file extension of our `ra_syntax/test_data/**` files to `.rast` they should be highlighted in vscode too.

The colors of the tokens are actually going to be color-theme dependent, or you can customize them via:
```jsonc
{
    "editor.tokenColorCustomizations": {
        "textMateRules": [ { "scope": "name", "settings": { /* */ } } ] 
    }
}
```
![image](https://user-images.githubusercontent.com/36276403/78204947-99f9d600-74a3-11ea-8315-cb1c87810c7c.png)

Related: #3682

Co-authored-by: veetaha <veetaha2@gmail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/editors/code/src/commands/syntax_tree.ts b/editors/code/src/commands/syntax_tree.ts
index ad98786171e..8d71cb39e31 100644
--- a/editors/code/src/commands/syntax_tree.ts
+++ b/editors/code/src/commands/syntax_tree.ts
@@ -15,6 +15,9 @@ export function syntaxTree(ctx: Ctx): Cmd {
     void new AstInspector(ctx);
 
     ctx.pushCleanup(vscode.workspace.registerTextDocumentContentProvider(AST_FILE_SCHEME, tdcp));
+    ctx.pushCleanup(vscode.languages.setLanguageConfiguration("ra_syntax_tree", {
+        brackets: [["[", ")"]],
+    }));
 
     return async () => {
         const editor = vscode.window.activeTextEditor;
@@ -36,7 +39,7 @@ export function syntaxTree(ctx: Ctx): Cmd {
 }
 
 class TextDocumentContentProvider implements vscode.TextDocumentContentProvider {
-    readonly uri = vscode.Uri.parse('rust-analyzer://syntaxtree');
+    readonly uri = vscode.Uri.parse('rust-analyzer://syntaxtree/tree.rast');
     readonly eventEmitter = new vscode.EventEmitter<vscode.Uri>();