keg_relocate: fix relocation of frameworks

When fixing references to regular dylibs, it is sufficient to search for
a file with the same base name, e.g., `libpoppler.56.dylib`. However, if
the broken reference is to a framework, we also have to take into
account preceding path components to find a suitable match. Framework
references (according to the `dyld` man page) come in two flavors:

- `XXX.framework/Versions/YYY/XXX` (with version)
- `XXX.framework/XXX` (without version)

The change here is to detect these patterns and to make sure that the
fixed library reference has the same suffix as the broken one.

Prior to this fix, a broken framework reference (if originating in a
sister framework) to `QtXml.framework/Versions/5/QtXml` would have been
rewritten to `<qt5-keg>/lib/QtXml.framework/QtXml`. In practice, this
mostly works, but is technically incorrect and thus creates problems
like in Homebrew/homebrew#42191. With this fix, the framework reference is correctly
rewritten to `<qt5-keg>/lib/QtXml.framework/Versions/5/QtXml`.

Closes Homebrew/homebrew#45494.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>