Lookalike identifiers
=====================

Should look-alike identifiers be considered conflicting?

E.g. `admin` and `adnin`?

Perhaps normalize like this:

    i_ -> L
    l  -> i
    n  -> m
    rn -> m
    I  -> i
    I_ -> L
    0  -> O
    1  -> i
    1_ -> L
    2  -> Z
    5  -> S

But there needs to be a special case for single-letter variables
(or segments of names), e.g.:

    m       n
    m0      n0
    arr_m   arr_n
    arr_m0  arr_n0
    

Maybe also (but these break hexadecimal numbers!):

    c1 -> d
    6  -> b
    8 -> B

And perhaps forbid the following

    __  (double underscore)