* refactor: format all C files under nvim
* refactor: disable formatting for Vim-owned files:
* src/nvim/indent_c.c
* src/nvim/regexp.c
* src/nvim/regexp_nfa.c
* src/nvim/testdir/samples/memfile_test.c
Initially we will use this for the popupmenu, floating windows will
follow soon
NB: writedelay + compositor is weird, we need more flexible
redraw introspection.