Add -ach {^s} orthography rule

[hftf]

Words like attach, detach, spinach currently get pluralized as attachs, detachs, spinachs.

[Vermoot]

I've been looking at the list of words the orthography rules follow (american_english_words.txt) and it seems that words ending in "ach" that get pluralized as "aches" might be the exception, rather than the rule.

From what I see, trying with every consonant with "-ach" after it, most of them make a k sound, for example "stomach", and those would be pluralized with just an S, and not "es".

I might be wrong, but I think not adding "-ach" to the regex for orthography rules might be better?