This allows to more quickly skip though regions which has non-decorative
marks when redrawing. This might seem like a gratuitous
micro-optimization in isolation.
But!
Soon decorations are gonna crop into other hot inner-loop paths,
including the plines.c code for calculating the horizontal and
vertical space of text. Then we want to quickly skip over regions with
"only" overlaying decorations (which do not affect text size)
* 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
This is inspired by Atom's "marker index" data structure to efficiently
adjust marks to text insertions deletions, but uses a wide B-tree
(derived from kbtree) to keep the nesting level down.
