* add `BF_ERROR` to identify error source buffers and use it with `next-error`.
* show `HELP` and `ERROR` buffer flags in `describe-buffer`.
* add a dedicated compilation mode with the following bindings:
* `next-error` on `n`, `M-n`
* `previous-error` on `p`, `M-p`
* `scroll-up` on `SPC`
* `scroll-down` on `DEL`
* `search-forward` on `/`
and the following new commands:
* `goto-error` on `RET`, `LF`
* `kill-compilation` on `C-c C-k`
* use `compilation` mode instead of `pager` mode for
`do-compile`, and switch interactive shell buffers to
`compilation` mode when the shell exits (if `shell_buffer_read_only` is set)
* refine popup/sidepane closing in `next-error`:
* remove unnecessary popup check, as the command cannot
be invoked if a popup window is present.
* use `do_delete_window` to close side pane to avoid
screen gap bug with `edit_close`.
f71fc6f25b