Automated compatible models list for task guides (#21338)

* initial commit. added tip placeholders and a script

* removed unused imports, fixed paths

* fixed generated links

* make style

* split language modeling doc into two: causal language modeling and masked language modeling

* added check_task_guides.py to make fix-copies

* review feedback addressed

.circleci/config.yml

@@ -178,6 +178,7 @@ jobs:
             - run: make deps_table_check_updated
             - run: python utils/tests_fetcher.py --sanity_check
             - run: python utils/update_metadata.py --check-only
+            - run: python utils/check_task_guides.py
 
 workflows:
     version: 2