Add bash-completion in the install

docs/bash-completion/flameshot

@@ -0,0 +1,59 @@
+# bash-completion for flameshot command
+# To be installed in "/usr/share/bash-completion/completions/flameshot"
+
+_flameshot() {
+	local prev cur cmd gui_opts full_opts config_opts
+	COMPREPLY=()
+
+	prev="${COMP_WORDS[COMP_CWORD-1]}"
+	cur="${COMP_WORDS[COMP_CWORD]}"
+	cmd="gui full config"
+	gui_opts="--path --delay -p -d"
+	full_opts="--path --delay --clipboard -p -d -c"
+	config_opts="--contrastcolor --filename --maincolor --showhelp --trayicon -k -f -m -s -t"
+
+	case "${prev}" in
+		gui)
+			COMPREPLY=( $(compgen -W "$gui_opts --help -h" -- ${cur}) )
+			return 0
+			;;
+		full)
+			COMPREPLY=( $(compgen -W "$full_opts --help -h" -- ${cur}) )
+			return 0
+			;;
+		config)
+			COMPREPLY=( $(compgen -W "$config_opts --help -h" -- ${cur}) )
+			return 0
+			;;
+		-f|--filename|-p|--path)
+			_filedir -d
+			return 0
+			;;
+		-s|--showhelp|-t|--trayicon)
+			COMPREPLY=( $(compgen -W "true false" -- ${cur}) )
+			return 0
+			;;
+		-d|--delay|-h|--help|-c|--clipboard|--version|-v)
+			return 0
+			;;
+		*)
+		;;
+	esac
+
+	# Options
+	case "${cur}" in
+		-*)
+			COMPREPLY=( $( compgen -W "--version --help -v -h" -- ${cur}) )
+			return 0
+			;;
+		--*)
+			COMPREPLY=( $( compgen -W "--version --help" -- ${cur}) )
+			return 0
+			;;
+		*)
+			COMPREPLY=( $( compgen -W "${cmd}" -- ${cur}) )
+			return 0
+			;;
+	esac
+}
+complete -F _flameshot flameshot