Find places that are currently relying on diagnostic-specific message
types to issue diagnostics and replace these with calls to the new
diagnostic methods.
Enhance `cmake --trace` (and related modes) by adding a backtrace for
the "end" command after "replaying" control structures.
Expand the unit test to include control structures.
Fixes: #27381
Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`, now with "east const" enforcement.
Use `clang-format` version 18.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Issue: #26123