Add Diff language (#19129)

docs/src/languages/diff.md

@@ -0,0 +1,17 @@
+# Diff
+
+Diff support is available natively in Zed.
+
+- Tree Sitter: [zed-industries/the-mikedavis/tree-sitter-diff](https://github.com/the-mikedavis/tree-sitter-diff)
+
+## Configuration
+
+Zed will not attempt to format diff files and has [`remove_trailing_whitespace_on_save`](https://zed.dev/docs/configuring-zed#remove-trailing-whitespace-on-save) and [`ensure-final-newline-on-save`](https://zed.dev/docs/configuring-zed#ensure-final-newline-on-save) set to false.
+
+Zed will automatically recognize files with `patch` and `diff` extensions as Diff files. To recognize other extensions, add them to `file_types` in your Zed settings.json:
+
+```json
+  "file_types": {
+    "Diff": ["dif"]
+  },
+```