Markdown linter (#1309)

* Add markdown linting

- add linter default rules
- adapt rules to current code
- fix the code for linting to pass
- add CI check

fix #1243

* Fix markdown for Substrate
* Fix tooling install
* Fix workflow
* Add documentation
* Remove trailing spaces
* Update .github/.markdownlint.yaml

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Fix mangled markdown/lists
* Fix captalization issues on known words

substrate/frame/README.md

@@ -1,11 +1,12 @@
 # FRAME
 
-The FRAME development environment provides modules (called "pallets") and support libraries that you can use, modify, and extend to build the runtime logic to suit the needs of your blockchain.
+The FRAME development environment provides modules (called "pallets") and support libraries that you can use, modify,
+and extend to build the runtime logic to suit the needs of your blockchain.
 
-### Documentation
+## Documentation
 
 https://docs.substrate.io/reference/frame-pallets/
 
-### Issues
+## Issues
 
 https://github.com/orgs/paritytech/projects/40