Add help documentation for pipeline run (#335)

Documentation after `/gitlab help` was missing in the output.

Ticket: #331

server/command.go

@@ -32,6 +32,7 @@ const commandHelp = `* |/gitlab connect| - Connect your Mattermost account to yo
 	* label:"<labelname>" - must include "merges" or "issues" in feature list when using a label
     * Defaults to "merges,issues,tag"
 * |/gitlab subscriptions delete owner/repo| - Unsubscribe the current channel from a repository
+* |/gitlab pipeline run [owner]/repo [ref]| - Run a pipeline for specific repository and ref (branch/tag)
 * |/gitlab me| - Display the connected GitLab account
 * |/gitlab settings [setting] [value]| - Update your user settings
   * |setting| can be "notifications" or "reminders"
@@ -98,7 +99,7 @@ func (p *Plugin) getCommand(config *configuration) (*model.Command, error) {
 	return &model.Command{
 		Trigger:              "gitlab",
 		AutoComplete:         true,
-		AutoCompleteDesc:     "Available commands: connect, disconnect, todo, me, settings, subscriptions, webhook, and help",
+		AutoCompleteDesc:     "Available commands: connect, disconnect, todo, me, settings, subscriptions, webhook, pipeline and help",
 		AutoCompleteHint:     "[command]",
 		AutocompleteData:     getAutocompleteData(config),
 		AutocompleteIconData: iconData,