[Bug]: `plural()` incorrectly pluralizes certain compound terms

[AlessandroMiola]

Hello and kudos for the great library!
I've encountered the following issue, which is breaking my pipeline.

import inflect

_infl = inflect.engine()
_infl.plural("Old technology")   # 'Old technologys'

while

import inflect

_infl = inflect.engine()
_infl.plural("technology")   # 'technologies'

Would you be open to supporting it or do you have a different opinion/view?
I also noticed some issues with pluralizing capitalized terms, but I saw there’s already an open issue for that (#201).

Thank you!

UPDATE

So, I've noticed that the lowered version works, so perhaps the issue falls under the scope of the one referenced above.

import inflect

_infl = inflect.engine()
_infl.plural("old technology")   # 'old technologies'

[ngdangtu-vn]

That's very funny because in my case, the bug happens differently, specifically it's broken when _ character space for word:

import inflect

en = inflect.engine()

def fail(singular: str) -> str:
    return en.plural_noun(singular, 2)

def work(singular: str) -> str:
    return en.plural_noun(singular.replace('_', ' '), 2).replace(' ', '_')

print(
  f"pass: {work('tag_alias')}\n", # tag_aliases
  f"fail: {fail('tag_alias')}\n", # tag_aliass
)