gettext Language Support for Visual Studio Code

Adds syntax highlight to po, pot and potx files.

Source tmLanguage file: https://github.com/textmate/gettext.tmbundle/blob/master/Syntaxes/Gettext.tmLanguage

Features

• vscgettext.moveToNextUntranslated: Move focus to next untranslated message (alt+n)
• vscgettext.moveToPreviousUntranslated: Move focus to previous untranslated message (alt+shift+n)