Em-dash treated as letter rather than punctuation

[IFcoltransG]

In a sentence that uses em-dashes without separating whitespace, like "The fox—a quick one—jumps over the lazy dog." the extension will mark fox—a and one—jumps as incorrectly spelt words, even though each one is actually two correct words.

I did not find any configuration for marking certain characters as whitespace.

[IFcoltransG]

I have added "/—/" as an ignore RegEx, which solves this problem.