Update docs for inlay hints (#8178)

Follow up of #7943. 
Updates the docs for inlay hints as they are incorrect (for Svelte).

Release Notes:

- N/A

docs/src/languages/rust.md

@@ -3,7 +3,42 @@
 - Tree Sitter: [tree-sitter-rust](https://github.com/tree-sitter/tree-sitter-rust)
 - Language Server: [rust-analyzer](https://github.com/rust-lang/rust-analyzer)
 
-### Target directory
+## Inlay Hints
+
+The following configuration can be used to enable inlay hints for rust:
+
+```json
+"inlayHints": {
+  "maxLength": null,
+  "lifetimeElisionHints": {
+  "useParameterNames": true,
+    "enable": "skip_trivial"
+  },
+  "closureReturnTypeHints": {
+    "enable": "always"
+  }
+}
+```
+
+to make the language server send back inlay hints when Zed has them enabled in the settings.
+
+Use
+
+```json
+"lsp": {
+  "$LANGUAGE_SERVER_NAME": {
+    "initialization_options": {
+      ....
+    }
+  }
+}
+```
+
+to override these settings.
+
+See https://rust-analyzer.github.io/manual.html#inlay-hints for more information.
+
+## Target directory
 
 The `rust-analyzer` target directory can be set in `initialization_options`: