Word delete only deletes until first accent/special char

[kevinansfield]

Word deletion (Alt+Backspace/Delete) will only delete until the first character with an accent. This differs from default OS behaviour, at least on macOS (Windows needs testing).

Mobiledoc-kit:

Normal textarea (macOS):

[kevinansfield]

The issue is arising because of the basic /\w|_|:/ word char regex in the position class that is used in the word unit movements. JavaScript's unicode support is pretty much non-existent for RegExp without resorting to an external library like XRegExp and vastly expanding the ranges of characters to cover all the possible languages that may be used.

However, if the custom delete key handler is removed then the default OS behaviour returns which is much preferred.

@mixonic do you know if the custom handler is there purely so that it can be wrapped in will/did-delete hook callbacks or does it also cover up some browser inconsistencies?