add lint check for .rst files incorrectly placed in the top-level dir, also bump blocklint version

.pre-commit-config.yaml

@@ -49,7 +49,15 @@ repos:
     -   id: mypy
         exclude: tests/
 -   repo: https://github.com/PrincetonUniversity/blocklint
-    rev: v0.2.4
+    rev: v0.2.5
     hooks:
     -   id: blocklint
         exclude: 'docs/Makefile|docs/release_notes.rst|tox.ini'
+-   repo: local
+    hooks:
+    -   id: check-rst-files
+        name: Check for .rst files in the top-level directory
+        entry: sh -c 'ls *.rst 1>/dev/null 2>&1 && { echo "found .rst file in top-level folder"; exit 1; } || exit 0'
+        language: system
+        always_run: true
+        pass_filenames: false