There are times (e.g. `ocaml`) when the `text_executable?` test will
match even although `file` does not consider it a text file. Ensure
that it's relocated in this case correctly.
References Homebrew/homebrew#41663.
ClosesHomebrew/homebrew#41926.
Work out what's text and what's not using `file`. Also, rename
`keg_fix_install_names` to `keg_relocate` because that's a more
accurate description of what it does now.
ClosesHomebrew/homebrew#41663.
Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>