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

polkadot/roadmap/implementers-guide/src/runtime/configuration.md

@@ -1,6 +1,11 @@
 # Configuration Pallet
 
-This module is responsible for managing all configuration of the parachain host in-flight. It provides a central point for configuration updates to prevent races between configuration changes and parachain-processing logic. Configuration can only change during the session change routine, and as this module handles the session change notification first it provides an invariant that the configuration does not change throughout the entire session. Both the [scheduler](scheduler.md) and [inclusion](inclusion.md) modules rely on this invariant to ensure proper behavior of the scheduler.
+This module is responsible for managing all configuration of the parachain host in-flight. It provides a central point
+for configuration updates to prevent races between configuration changes and parachain-processing logic. Configuration
+can only change during the session change routine, and as this module handles the session change notification first it
+provides an invariant that the configuration does not change throughout the entire session. Both the
+[scheduler](scheduler.md) and [inclusion](inclusion.md) modules rely on this invariant to ensure proper behavior of the
+scheduler.
 
 The configuration that we will be tracking is the [`HostConfiguration`](../types/runtime.md#host-configuration) struct.
 
@@ -23,7 +28,8 @@ The session change routine works as follows:
 
 - If there is no pending configurations, then return early.
 - Take all pending configurations that are less than or equal to the current session index.
-  - Get the pending configuration with the highest session index and apply it to the current configuration. Discard the earlier ones if any.
+  - Get the pending configuration with the highest session index and apply it to the current configuration. Discard the
+    earlier ones if any.
 
 ## Routines
 
@@ -41,17 +47,17 @@ pub fn configuration() -> HostConfiguration {
   Configuration::get()
 }
 
-/// Schedules updating the host configuration. The update is given by the `updater` closure. The 
-/// closure takes the current version of the configuration and returns the new version. 
-/// Returns an `Err` if the closure returns a broken configuration. However, there are a couple of 
-/// exceptions: 
+/// Schedules updating the host configuration. The update is given by the `updater` closure. The
+/// closure takes the current version of the configuration and returns the new version.
+/// Returns an `Err` if the closure returns a broken configuration. However, there are a couple of
+/// exceptions:
 ///
-/// - if the configuration that was passed in the closure is already broken, then it will pass the 
+/// - if the configuration that was passed in the closure is already broken, then it will pass the
 /// update: you cannot break something that is already broken.
 /// - If the `BypassConsistencyCheck` flag is set, then the checks will be skipped.
 ///
 /// The changes made by this function will always be scheduled at session X, where X is the current session index + 2.
-/// If there is already a pending update for X, then the closure will receive the already pending configuration for 
+/// If there is already a pending update for X, then the closure will receive the already pending configuration for
 /// session X.
 ///
 /// If there is already a pending update for the current session index + 1, then it won't be touched. Otherwise,
@@ -61,4 +67,6 @@ fn schedule_config_update(updater: impl FnOnce(&mut HostConfiguration<BlockNumbe
 
 ## Entry-points
 
-The Configuration module exposes an entry point for each configuration member. These entry-points accept calls only from governance origins. These entry-points will use the `update_configuration` routine to update the specific configuration field.
+The Configuration module exposes an entry point for each configuration member. These entry-points accept calls only from
+governance origins. These entry-points will use the `update_configuration` routine to update the specific configuration
+field.