salt sls files with python shebangs are not properly recognized

Some salt sls files are written in python directly, I've added those interpreters in a PR here https://github.com/chriskuehl/identify/pull/60 as well as disabled the executable checks since these files are not required to be and also disabled the optimization for skipping peeking at the file contents if we recognize the extension.. I do see how this a nice speedup though.. maybe the extensions.EXTENSIONS dict should be changed from:

EXTENSIONS = {
...
    'sh': {'text', 'shell'},
    'sls': {'text', 'salt'},
    'so': {'binary'},
...
}

to something like:

EXTENSIONS = {
...
    'sh': {
        'tags': {'text', 'shell'},
        },
    'sls': {
        'tags': {'text', 'salt'},
        'always-peek': True,
    },
    'so': {
        'tags': {'binary'},
    },
...
}

By changing each value to its own dict which could have an optional key always-peek(?) so then you could .get('always-peek', False) to check if the file should be inspected?

Start with the proposed changes in pull request #60 and inspect the extensions.EXTENSIONS mapping described in the issue. Trace how .sls files are classified, including executable checks and the extension-based content-peek optimization. Done means Python-shebang Salt SLS files are recognized without requiring executable permissions.