feat: More fine-grained --classify behavior

[planet36]

With the ‐‐classify option I like seeing a trailing slash on the directories. However I don't favor seeing other symbols after non-directories (because they affect word selection when double clicking).

ls has an --indicator-style option described in the info page as such:

‘--indicator-style=WORD’
     Append a character indicator with style WORD to entry names, as
     follows:

     ‘none’
          Do not append any character indicator; this is the default.
     ‘slash’
          Append ‘/’ for directories.  This is the same as the ‘-p’
          option.
     ‘file-type’
          Append ‘/’ for directories, ‘@’ for symbolic links, ‘|’ for
          FIFOs, ‘=’ for sockets, and nothing for regular files.  This
          is the same as the ‘--file-type’ option.
     ‘classify’
          Append ‘*’ for executable regular files, otherwise behave as
          for ‘file-type’.  This is the same as the ‘--classify’ (‘-F’)
          option.

Could something like this be considered for eza?