maOS "strip" hint formatted as a note, as requested

Documentation/how-to-build.rst

@@ -138,5 +138,5 @@ In order to do a rebuild you can issue a clean command to ninja via
 
 Otherwise, rerunning ``./bootstrap.sh`` will also clean the build-directory.
 
-- macOS: If ``strip`` fails to work on the freshly compiled mpy-cross: "strip: object: (...)/lib/micropython/micropython/mpy-cross/mpy-cross malformed object (unknown load command 9)", you a likely not using the `strip` that matches to your ``clang``. Do ``which strip && which clang``, and if the paths don't match, clean up your PATHs, or as a quick hack, create a symlink for strip. 
+.. note:: macOS: If ``strip`` fails to work on the freshly compiled mpy-cross: "strip: object: (...)/lib/micropython/micropython/mpy-cross/mpy-cross malformed object (unknown load command 9)", you a likely not using the `strip` that matches to your ``clang``. Do ``which strip && which clang``, and if the paths don't match, clean up your PATHs, or as a quick hack, create a symlink for strip.