Sanitize generated Mixin methods

[Johni0702]

Mixin is great, unfortunately its generated methods contain semi-random parts (to prevent conflicts):
https://openeye.openmods.info/crashes/ccfdcc458cd87da5d75d51493f740403
https://openeye.openmods.info/crashes/1901be9a40fe69ba7ca917288b83edf9
(note the slight difference in the handler$recordViewOnPlaySound$ line)

The pattern to their names is:
prefix$name$abc012 [source]
prefix depends on the source method (i.e. non-random) with valid values listed here (list may grow in the future, though probably not very often).
name depends on the source method (i.e. non-random, fully arbitrary)
abc are at least three semi-random letters (a-z and A-Z) [source]
012 is a semi-random hexadecimal number padded to at least three characters [source]