fix(folds): update folds in Insert mode with fdm=indent (#24402)

Previously, when using foldmethod=indent, inserting an unindented line
would inadvertently open closed folds below it.
As a performance improvement, folds were only updated once, across all
lines, after Insert mode was exited.

Now, the performance improvement is no longer being used when
foldmethod=indent, so folds are updated multiple times during Insert
mode, but only across the lines that are changing, which preserves the
folds (and their open/close states) instead of recreating them.

0 files changed, 0 insertions, 0 deletions