Valid filetypes are hard to discover

[harristom]

I opened a config file and wanted to set the filetype to get some syntax highlighting. I tried "set filetype sh" which didn't work, but "set filetype shell" did (I had expected that using a valid file extension would do it). I couldn't find a list of valid filetypes in the documentation, and tab completion didn't work on this command to provide a list of valid options in the way it does when setting a colorscheme.

[zyedidia]

This is a valid point, and perhaps we can introduce some tab completion for this case. For the time being, you can look through the syntax files at https://github.com/zyedidia/micro/tree/master/runtime/syntax. If you open a file, the filetype name should be listed at the top.

@dmaluka @JoeKar for close? because of #3090

[JoeKar]

Closed with #3090.