Capture plus and minus metadata injections

[mattmassicotte]

While testing out the injections, I noticed that plus/minus metadata wasn't being correctly captured.

I also removed the mention of nvim-treesitter, because at this point, it has diverged. They've done truly amazing work with tree-sitter, but I really feel like the parser data should live with the parsers. When possible, one source of truth just makes sense.

[MDeiml]

Thanks, good changes! I guess the other yaml injection should be removed, but that's another story.

[mattmassicotte]

Thank you!

To be honest, I wasn't sure I understood that other yaml injection, so I just left it as-is.