Pull changes from magazine.nvim fork

[iguanacucumber]

Hi, around a month ago i made a fork of nvim-cmp, and it's core sources, because i had a bug that made nvim-cmp almost unusable (see #2038 ), and i wanted a bit more speed since i was on a very slow laptop ( see #1935 ). So at first i made this fork for myself, by combining those 2 PR, and i thought, why not make others profit from it ? So i made some changes myself and implemented some PRs. So this "fork" (magazine.nvim) and the "fork" of the sources (mag-*) mostly fixes bugs and add some features.

To try out this fork, check magazine.nvim README