Support help and man buffers

[adoyle-h]

Neovim builtin gO can open an outline in help and :Man buffers. https://neovim.io/doc/user/various.html#gO . But it looks not good.

Can aerial support help and man buffers? Currently it shows Aerial could find no supported backend.

My config:

backends = {
	['_'] = { 'lsp', 'treesitter' },
	markdown = { 'markdown' },
},

[stevearc]

I've added support for help files. Man is trickier because there's no treesitter parser for it, but it should still be possible.

[stevearc]

Man page support added

[adoyle-h]

It's excellent! Thank you so much. @stevearc