Description

This PR adds support for M3U playlists, a widespread format for queueing media for playback, specifying the location of streaming endpoints for online radio, and so forth. The M3U format was created by the Fraunhofer Society for their WinPlay3 software, an early MP3 player for Windows. Since then, it's become a de facto standard for defining media playlists.

Checklist

• I am adding a new language.
  • The extension of the new language is used in hundreds of repositories on GitHub:
    • ~216,000 results for .m3u
    • ~139,000 results for .m3u8
  • I have included real-world usage samples for each extension:
    • Bolt Thrower - Those Once Loyal.m3u: Created by yours truly
    • M+.m3u8: From ahmadbizar/m3u8, MIT license
    • au.m3u: From nsm-lab/iptv, The Unlicense
    • gn.m3u: From nsm-lab/iptv, The Unlicense
  • I have included a syntax highlighting grammar
    One that I wrote yesterday and added to the usual pile of grammars in language-etc.
  • I have added a colour:
    • Hex value: #179C7D
    • Rationale: The colour was taken from the logo of Fraunhofer, the mob who originally created the M3U format.
  • I have updated the heuristics to distinguish my language from others using the same extension.