clangd based code model can't rename macros

See https://github.com/clangd/clangd/issues/729 and discussion on https://codereview.qt-project.org/c/qt-creator/qt-creator/+/470253

This report is mainly to keep track of whether renaming macros is expected to work in Creator, so Squish testing of the feature can be enabled automatically.

Found by Squish test tst_rename_macros.