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/docker/README.md

@@ -1,27 +1,32 @@
 # Substrate Builder Docker Image
 
-The Docker image in this folder is a `builder` image. It is self contained and allows users to build the binaries themselves.
-There is no requirement on having Rust or any other toolchain installed but a working Docker environment.
+The Docker image in this folder is a `builder` image. It is self contained and allows users to build the binaries
+themselves. There is no requirement on having Rust or any other toolchain installed but a working Docker environment.
 
-Unlike the `parity/polkadot` image which contains a single binary (`polkadot`!) used by default, the image in this folder builds and contains several binaries and you need to provide the name of the binary to be called.
+Unlike the `parity/polkadot` image which contains a single binary (`polkadot`!) used by default, the image in this
+folder builds and contains several binaries and you need to provide the name of the binary to be called.
 
-You should refer to the [.Dockerfile](./substrate_builder.Dockerfile) for the actual list. At the time of editing, the list of included binaries is:
+You should refer to the [.Dockerfile](./substrate_builder.Dockerfile) for the actual list. At the time of editing, the
+list of included binaries is:
 
-- substrate
-- subkey
-- node-template
-- chain-spec-builder
+- `substrate`
+- `subkey`
+- `node-template`
+- `chain-spec-builder`
 
 First, install [Docker](https://docs.docker.com/get-docker/).
 
-Then to generate the latest parity/substrate image. Please run:
+Then to generate the latest `parity/substrate` image. Please run:
 ```sh
 ./build.sh
 ```
 
-> If you wish to create a debug build rather than a production build, then you may modify the [.Dockerfile](./substrate_builder.Dockerfile) replacing `cargo build --locked --release` with just `cargo build --locked` and replacing `target/release` with `target/debug`. 
+If you wish to create a debug build rather than a production build, then you may modify the
+[.Dockerfile](./substrate_builder.Dockerfile) replacing `cargo build --locked --release` with just
+`cargo build --locked` and replacing `target/release` with `target/debug`.
 
-> If you get an error that a tcp port address is already in use then find an available port to use for the host port in the [.Dockerfile](./substrate_builder.Dockerfile).
+If you get an error that a tcp port address is already in use then find an available port to use for the host port in
+the [.Dockerfile](./substrate_builder.Dockerfile).
 
 The image can be used by passing the selected binary followed by the appropriate tags for this binary.
 
@@ -32,7 +37,8 @@ Your best guess to get started is to pass the `--help flag`. Here are a few exam
 - `./run.sh node-template --version`
 - `./run.sh chain-spec-builder --help`
 
-Then try running the following command to start a single node development chain using the Substrate Node Template binary `node-template`:
+Then try running the following command to start a single node development chain using the Substrate Node Template binary
+`node-template`:
 
 ```sh
 ./run.sh node-template --dev --ws-external