1- Remove `parser.trim`, it was only being used in 1 place. All other places
are using `std.mem.trim(u8, X, &std.ascii.whitespace)`, so i updated MIME to
use this as well
2- Use slightly more meaningful field name, i => pos, s = data
3- Leverage std.mem.indexOfScalarPos which can be more efficient for longer
inputs (since it leverages SIMD)
688cb55c2b