make clang-tidy recognize .H as a header

[zingale]

PR summary

PR motivation

PR checklist

• test suite needs to be run on this PR
• this PR will change answers in the test suite to more than roundoff level
• all newly-added functions have docstrings as per the coding conventions
• the CHANGES file has been updated, if appropriate
• if appropriate, this change is described in the docs

[yut23]

This gives an error for me with clang-tidy 15.0.7:

/home/eric/dev/Castro/.clang-tidy:50:1: error: unknown key 'HeaderFileExtensions'
HeaderFileExtensions: ['', "H", 'h', 'hh', 'hpp', 'hxx']
^~~~~~~~~~~~~~~~~~~~
Error parsing /home/eric/dev/Castro/.clang-tidy: Invalid argument

It looks like the global option was only added in LLVM 17. Manually setting the check-specific options appears to work fine (found with https://releases.llvm.org/16.0.0/tools/clang/tools/extra/docs/search.html?q=HeaderFileExtensions):

CheckOptions:
  bugprone-suspicious-include.HeaderFileExtensions: ';H;h;hh;hpp;hxx'
  google-build-namespaces.HeaderFileExtensions: ',H,h,hh,hpp,hxx'
  google-global-names-in-headers.HeaderFileExtensions: ',H,h,hh,hpp,hxx'
  llvm-header-guard.HeaderFileExtensions: ',H,h,hh,hpp,hxx'
  misc-definitions-in-headers.HeaderFileExtensions: ',H,h,hh,hpp,hxx'
  misc-unused-using-decls.HeaderFileExtensions: ',H,h,hh,hpp,hxx'  # since LLVM 16
  misc-use-anonymous-namespace.HeaderFileExtensions: ';H;h;hh;hpp;hxx'  # since LLVM 16

[zingale]

indeed. It only works with clang-tidy >= 17

see: AMReX-Codes/amrex#3832