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/utility/README.md

@@ -27,10 +27,10 @@ filtered by any proxy.
 ### Dispatchable Functions
 
 #### For batch dispatch
-* `batch` - Dispatch multiple calls from the sender's origin.
+- `batch` - Dispatch multiple calls from the sender's origin.
 
 #### For pseudonymal dispatch
-* `as_derivative` - Dispatch a call from a derivative signed origin.
+- `as_derivative` - Dispatch a call from a derivative signed origin.
 
 [`Call`]: ./enum.Call.html
 [`Config`]: ./trait.Config.html