Add more irregular words

[hkdobrev]

Any help with the tests is appreciated!

[olvlvl]

Thanks for your contribution! I left a comment, it should fix the issues. I'm in an hackathon until Saturday. If the problem persist I'll have a look next week.

[hkdobrev]

@olvlvl I don't get why this

	->singular('/^are$/i`', 'is')
	->singular('/^were$/i`', 'was')
	->singular('/^have$/i`', 'has')

would break the tests as I have added ^ and $. Am I missing something? I suspect there could be a deeper issue behind this.

[olvlvl]

Please rebase.

[hkdobrev]

Please rebase.

✅ Done.