This applies especially in lsp-mode. Yasnippet snippets now show as
completion candidates if the word at point exactly matches a snippet
keyword, otherwise it'll fallback to normal lsp backed completion.
And it also supports completing file/directory names now too while
lsp-mode is active.
All this is done by modifying completion-at-point-functions after
lsp-mode has done it's trickery with it. Along with a dirty hack to
company-yasnippet to make it only activate on exact matches. Without
this hack, lsp backed completion rarely activates as snippets would have
higher priority if there's any partial matches.
There are a few major modes which are not based on prog-mode, that I
want to behave like prog-mode. Previously each did nearly all the same
setup that's done via the prog-mode hooks. Now instead let's actually
run runs the hooks for prog-mode.
The original code to fix the incompatibility didn't see to work anymore,
so refactored it a bit to so it goes about things a bit more carefully,
and that seemed to fix it.
