fix(change): update fold after on_bytes (#26364)

Problem:
With vim.treesitter.foldexpr, `o`-ing two lines above a folded region
opens the fold. This does not happen with legacy foldexprs. For example,
make a markdown file with the following text (without indentation),
enable treesitter fold, and follow the instruction in the text.

    put cursor on this line and type zoo<Esc>
    initially folded, revealed by zo
    # then this fold will be opened
    initially folded, revealed by o<Esc>

Analysis:
* `o` updates folds first (done in `changed_lines`), evaluating
  foldexpr, and then invokes `on_bytes` (done in `extmark_splice`).
* Treesitter fold allocates the foldinfo for added lines (`add_range`)
  on `on_bytes`.
* Therefore, when treesitter foldexpr is invoked while running `o`, it
  sees outdated foldinfo.

Solution:
`extmark_splice`, and then `changed_lines`. This seems to be the
standard order in other places, e.g., `nvim_buf_set_lines`.

0 files changed, 0 insertions, 0 deletions