Locator: Add longer description to filters

This is shown as tool tips in the location options, and if any platform
supports this also as tool tips on the menu actions of the locator input
field.

Change-Id: I8b439e45e6097a16a5f932d25d4e5d3e9bddb6ad
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/git/gitplugin.cpp

@@ -662,6 +662,7 @@ GitPluginPrivate::GitPluginPrivate()
 
     const QString prefix = "git";
     m_commandLocator = new CommandLocator("Git", prefix, prefix, this);
+    m_commandLocator->setDescription(tr("Triggers a Git version control operation."));
 
     //register actions
     ActionContainer *toolsContainer = ActionManager::actionContainer(Core::Constants::M_TOOLS);