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
This presents value semantics for a stack of constant values.
Internally it shares ownership to avoid copies. Previously
this was implemented by `cmListFileBacktrace` explicitly,
but the approach can be re-used for other kinds of stacks.