It is less error-prone than manually defining header guards. Pretty much
all compilers support it even if it's not part of the C standard.

problem: breakcheck might run arbitrary lua code, which might require
modules and thus invoke runtime path calculation recursively.
solution: Block the use of breakcheck when expanding glob patterns
inside 'runtimepath'

fixes #23012

Fix remaining clint errors and remove error suppression completely.

Rename the lint targets to align with the established naming convention:

- lintc-clint lints with clint.py.
- lintc-uncrustify lints with uncrustify.
- lintc runs both targets.

lintc is also provided as a make target for convenience.

After this change we can remove these files:
https://github.com/neovim/doc/tree/gh-pages/reports/clint
https://github.com/neovim/doc/blob/main/ci/clint-errors.sh

Done automatically using the following perl command:

  perl -pi -0777pe 's#\n\K */\*\n(.+?)\s*\*/\n#join("\n", map { $_ =~ s:^\s*\K \*://:; $_ } split("\n", $1)) . "\n"#sge' src/nvim/**/*.c

Co-authored-by: zeertzjq <zeertzjq@outlook.com>

Co-authored-by: zeertzjq <zeertzjq@outlook.com>

* 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