Problem:  SpotBugs compiler can be further improved
Solution: Introduce event-driven primitives for SpotBugs
          (Aliaksei Budavei)

closes: vim/vim#16258

https://github.com/vim/vim/commit/2e252474c4df5018b9819d86ebb70bf3b1b1a1af

Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>

Problem:  SpotBugs compiler can be improved
Solution: runtime(compiler): Improve defaults and error handling for
          SpotBugs; update test_compiler.vim (Aliaksei Budavei)

runtime(compiler): Improve defaults and error handling for SpotBugs

* Keep "spotbugs#DefaultPreCompilerTestAction()" defined but
  do not assign its Funcref to the "PreCompilerTestAction"
  key of "g:spotbugs_properties": there are no default and
  there can only be introduced arbitrary "*sourceDirPath"
  entries; therefore, this assignment is confusing at best,
  given that the function's implementation delegates to
  whatever "PreCompilerAction" is.

* Allow for the possibility of relative source pathnames
  passed as arguments to Vim for the Javac default actions,
  and the necessity to have them properly reconciled when
  the current working directory is changed.

* Do not expect users to remember or know that new source
  files ‘must be’ ":argadd"'d to be then known to the Javac
  default actions; so collect the names of Java-file buffers
  and Java-file Vim arguments; and let users providing the
  "@sources" file-lists in the "g:javac_makeprg_params"
  variable update these file-lists themselves.

* Strive to not leave behind a fire-once Syntax ":autocmd"
  for a Java buffer whenever an arbitrary pre-compile action
  errors out.

* Only attempt to run a post-compiler action in the absence
  of failures for a pre-compiler action.  Note that warnings
  and failures are treated alike (?!) by the Javac compiler,
  so when previews are tried out with "--enable-preview",
  remember about passing "-Xlint:-preview" too to also let
  SpotBugs have a go.

* Properly group conditional operators when testing for key
  entries in a user-defined variable.

* Also test whether "javaExternal" is defined when choosing
  an implementation for source-file parsing.

* Two commands are provided to toggle actions for buffer-local
  autocommands:
  - SpotBugsRemoveBufferAutocmd;
  - SpotBugsDefineBufferAutocmd.

For example, try this from "~/.vim/after/ftplugin/java.vim":
------------------------------------------------------------
if exists(':SpotBugsDefineBufferAutocmd') == 2
	SpotBugsDefineBufferAutocmd BufWritePost SigUSR1
endif
------------------------------------------------------------

And ":doautocmd java_spotbugs User" can be manually used at will.

closes: vim/vim#16140

https://github.com/vim/vim/commit/368ef5a48c7a41af7fe2c32a5d5659e23aff63d0

Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>

Uses an overload to properly show the different return type based on the
input parameter.

Problem:  filetype: just files are not recognized
Solution: adjust filetype detection pattern, detect just shebang line,
          include just ftplugin, indent and syntax plugin
          (Peter Benjamin)

closes: vim/vim#16466

https://github.com/vim/vim/commit/72755b3c8e91ec90447969b736f080e0de36003d

Co-authored-by: Peter Benjamin <petermbenjamin@gmail.com>

https://github.com/vim/vim/commit/4335fcfed1b0a29c07b10f97d1f309dd8f964de6

Co-authored-by: Christian Brabandt <cb@256bit.org>

- highlight more C keywords, including some from C23

Conditionally highlight C23 features:
- #embed, #elifdef and #elifndef preprocessor directives
- predefined macros
- UTF-8 character constants
- binary integer constants, _BitInt literals, and digit separators
- nullptr_t type and associated constant
- decimal real floating-point, bit precise and char types
- typeof operators

Matchit:
- update for new preprocessor directives

fixes: vim/vim#13667
fixes: vim/vim#13679
closes: vim/vim#12984

https://github.com/vim/vim/commit/c2a967a1b9adca6c929e3dc5c218dfada00059b6

Co-authored-by: Doug Kearns <dougkearns@gmail.com>
Co-authored-by: Albin Ahlbäck <albin.ahlback@gmail.com>

Problem:
`yx` uses "y" prefix, which shadows a builtin operator.

Solution:
Use `g=` (in the form of `g==` currently), drawing from precedent of
CTRL-= and 'tpope/vim-scriptease'.

closes: vim/vim#16419

https://github.com/vim/vim/commit/51754c8a498c39592250a077f56db89dd261995d

Co-authored-by: Yochem van Rosmalen <git@yochem.nl>