Missing system frameworks message does not clearly instruct contributors on the required changes

[prince-chrismc]

          Feel free to update message hook if you think it's misleading.

Instead of:

post_package(): WARN: [MISSING SYSTEM LIBS (KB-H043)] Library './lib/libSDL2_ttf.dylib' links to system library 'CoreServices' but it is not in cpp_info.frameworks.

it could be:

post_package(): WARN: [MISSING SYSTEM LIBS (KB-H043)] Library './lib/libSDL2_ttf.dylib' links to system library 'CoreServices', therefore 'CoreServices' should be in cpp_info.frameworks if static, but it's missing.

Originally posted by @SpaceIm in conan-io/conan-center-index#18366 (comment)