Inconsistent spelling in docs for a few words

[Natalia Bidart]

While reviewing some PRs, I noticed a few inconsistencies in spelling:

• hardcode(d) / hard code / hard-code
• lookup / look up
• flatpage / flat page

Although tickets are not necessary for documentation changes, I think it would be helpful to track these and make decisions on the correct spelling so we can apply them consistently.

For the first case, I think we should use either hard-code or hardcode (but not hard code, and we should choose one and stick with it).
For the second, it seems that lookup is used as a noun or adjective, while the verb is look up. I tend to use lookup as a verb in the context of Django model DB operations, but I wonder if this is technically incorrect. If it's acceptable, I would be inclined to use lookup everywhere.
For the third, I believe we should use flatpage (without a space) when referring to the specific context of the Django contrib app, unless we're referring to any page that is flat, in general.

[Sarah Boyce]

Agree with the logic, accepting

[David Smith]

The AP style book doesn't have hard code but does have hard line which is likely close enough.

"Hard line" (n)
"Hard-liner" (n)
"Hard-line" (adj.)

[Natalia Bidart]

Replying to David Smith:

The AP style book doesn't have hard code but does have hard line which is likely close enough.

"Hard line" (n)
"Hard-liner" (n)
"Hard-line" (adj.)

Thank you, David. I did look into those, and also considered "hard core" as a similar reference. That said, given the majority of existing uses for hardcode, particularly in the Django docs and other technical contexts, I lean toward hardcode as the preferred form. Other sources like the ​Cambridge dictionary also list it as a verb, which supports this choice.

[nessita <124304+nessita@…>]

In abbcef52:

Refs #36311 -- Unified spelling of "flatpage" in docs/ref/contrib/flatpages.txt.

[nessita <124304+nessita@…>]

In be40289:

Fixed #36311 -- Unified spelling of "hardcode" and its variants in docs.

Co-authored-by: Natalia <124304+nessita@…>