Cleanup repo (a tiny bit) (#1382)

* Delete stale adoc files

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Convert adoc to md

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add adoc to gitignore

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Delete more random unmaintained files

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Markdown lint

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

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Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/bin/node/cli/doc/shell-completion.md

@@ -0,0 +1,34 @@
+# Shell completion
+
+The Substrate cli command supports shell auto-completion. For this to work, you will need to run the
+completion script matching your build and system.
+
+Assuming you built a release version using `cargo build --release` and use `bash` run the following:
+
+`source target/release/completion-scripts/substrate.bash`
+
+You can find completion scripts for:
+- bash
+- fish
+- zsh
+- elvish
+- powershell
+
+To make this change persistent, you can proceed as follows:
+
+```shell
+COMPL_DIR=$HOME/.completion
+mkdir -p $COMPL_DIR
+cp -f target/release/completion-scripts/substrate.bash $COMPL_DIR/
+echo "source $COMPL_DIR/substrate.bash" >> $HOME/.bash_profile
+source $HOME/.bash_profile
+```
+
+When you build a new version of Substrate, the following will ensure your auto-completion script matches the current binary:
+
+```shell
+COMPL_DIR=$HOME/.completion
+mkdir -p $COMPL_DIR
+cp -f target/release/completion-scripts/substrate.bash $COMPL_DIR/
+source $HOME/.bash_profile
+```