Problem:
As checkhealth grows, it is increasingly hard to quickly glance through
the information.

Solution:
Show a summary of ok, warn, and error outputs per section.

Problem:
Normally, `:drop +41 foo.txt` will open foo.txt with the cursor on line
41. But if foo.txt is already open, it instead is a no-op, even if the
cursor is on a different line.

Steps to reproduce:

    nvim --clean foo.txt
    :drop +30 foo.txt

Solution:
Handle +cmd in ex_drop().

Problem:  Logic computing the new height of the modified area does not
          take into account virtual lines attached to a folded line.

Solution: Remove `hasFolding()` branch and let `plines_win_full()` do its job.

Problem:  quickfix and location-list stack is limited to 10 items
Solution: add the 'chistory' and 'lhistory' options to configure a
          larger quickfix/location list stack
          (64-bitman)

closes: vim/vim#16920

https://github.com/vim/vim/commit/88d41ab270a8390a43da97a903b1a4d76b89d330

Co-authored-by: 64-bitman <60551350+64-bitman@users.noreply.github.com>
Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>

Problem:  If win_close() is called with a window that has quickfix stack
          attached to it, the corresponding quickfix buffer will be
          closed and freed after the buffer was already closed. At that
          time curwin->w_buffer points to NULL, which the CHECK_CURBUF
          will catch and abort if ABORT_ON_ERROR is defined
Solution: in wipe_qf_buffer() temporarily point curwin->w_buffer back to
          curbuf, the window will be closed anyhow, so it shouldn't
          matter that curbuf->b_nwindows isn't incremented.

closes: vim/vim#16993
closes: vim/vim#16985

https://github.com/vim/vim/commit/ce80c59bfd3c0087a354ee549639ca60fa192fba

Co-authored-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>

Problem:  Help files not detected when 'iskeyword' includes ":".
Solution: Do not use \< and \> in the pattern (zeertzjq).

fixes: vim/vim#17069
closes: vim/vim#17071

https://github.com/vim/vim/commit/e370141bf41919642061ee2e78340dca84678712

Problem:  An on_win-disabled decoration provider is left disabled for
          the on_buf callback during the next redraw (if the provider
          does not subscribe to on_end).

Solution: Move re-activation of the provider from after the on_end
          callback to before the on_start callback.

Problem:
nvim_buf_del_extmark error if buffer is destroyed before timer stops

Solution:
check nvim_buf_is_valid.

Problem:  inline word diff treats multibyte chars as word char
          (after 9.1.1243)
Solution: treat all non-alphanumeric characters as non-word characters
          (Yee Cheng Chin)

Previously inline word diff simply used Vim's definition of keyword to
determine what is a word, which leads to multi-byte character classes
such as emojis and CJK (Chinese/Japanese/Korean) characters all
classifying as word characters, leading to entire sentences being
grouped as a single word which does not provide meaningful information
in a diff highlight.

Fix this by treating all non-alphanumeric characters (with class number
above 2) as non-word characters, as there is usually no benefit in using
word diff on them. These include CJK characters, emojis, and also
subscript/superscript numbers. Meanwhile, multi-byte characters like
Cyrillic and Greek letters will still continue to considered as words.

Note that this is slightly inconsistent with how words are defined
elsewhere, as Vim usually considers any character with class >=2 to be
a "word".

related: vim/vim#16881 (diff inline highlight)
closes: vim/vim#17050

https://github.com/vim/vim/commit/9aa120f7ada592ed03b37f4de8ee413c5385f123

Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

Problem:  Successive autocmd verbose messages may be emitted without a kind.

Solution: Always set the kind when preparing to emit a verbose message.