Add PR labeler

Author: fwcd

.github/labeler.yml

@@ -0,0 +1,9 @@
+grammar:
+  - changed-files:
+    - any-glob-to-any-file:
+        - syntaxes/**/*
+
+extension:
+  - changed-files:
+    - any-glob-to-any-file:
+        - src/**/*

.github/workflows/labeler.yml

@@ -0,0 +1,15 @@
+name: "Pull Request Labeler"
+
+on:
+  - pull_request_target
+
+jobs:
+  triage:
+    permissions:
+      contents: read
+      pull-requests: write
+
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v5
+