Merge pull request #1804 from NoahGorny/cleanup/docker-completions

completion: Lint docker completion and add about-completion

clean_files.txt

@@ -62,6 +62,7 @@ completion/available/brew.completion.bash
 completion/available/cargo.completion.bash
 completion/available/conda.completion.bash
 completion/available/consul.completion.bash
+completion/available/docker.completion.bash
 completion/available/knife.completion.bash
 completion/available/packer.completion.bash
 completion/available/pipx.completion.bash

completion/available/docker.completion.bash

@@ -1,21 +1,24 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
+cite "about-completion"
+about-completion "docker completion"
 
 # Make sure docker is installed
 _command_exists docker || return
 
 # Don't handle completion if it's already managed
-complete -p docker &>/dev/null && return
+_completion_exists docker && return
 
 _docker_bash_completion_paths=(
-  # MacOS
-  '/Applications/Docker.app/Contents/Resources/etc/docker.bash-completion'
-  # Linux
-  '/usr/share/bash-completion/completions/docker'
+	# MacOS
+	'/Applications/Docker.app/Contents/Resources/etc/docker.bash-completion'
+	# Linux
+	'/usr/share/bash-completion/completions/docker'
 )
 
-for fn in "${_docker_bash_completion_paths[@]}" ; do
-  if [ -r "$fn" ] ; then
-    source "$fn"
-    break
-  fi
+for fn in "${_docker_bash_completion_paths[@]}"; do
+	if [ -r "$fn" ]; then
+		# shellcheck disable=SC1090
+		source "$fn"
+		break
+	fi
 done