Fix recent warnings seen on Rider 2024.3

[frenzibyte]

Not fully sure if this is caused by new Rider update or something else, I've navigated back to a point before #6434 was merged but it's not relevant, not to mention that the warnings fixed by this PR completely come from ReSharper, so they're not relevant to that PR anyway.

Fix enum naming warnings

This one was actually seen in ppy/osu as well half a year ago: ppy/osu#28051

It seems that it would be better to exclude enum members from naming rule inspections, but apparently that's not possible to do at all. Enum members are being treated the same as public fields/properties, and since we apply the pascal case rule to those, enum members are being affected as well.

This is an issue with Rider that was reported a long while ago but has not been fixed until now. For the time being, any existing enum causing a warning has been individually silenced until Rider responds or otherwise (there are rare enums which renaming them or adding abbreviations to silence them is viable so I've done that for them).

Demote "usage of default struct equality" inspection to hint

Looks to be a new Rider inspection, it's firing off as warnings in the following two places (screenshots were taken after severity was changed to hint):

Made it a hint for now, not confident about touching the source generation codebase just to appease this inspection (@smoogipoo you might be interested though)

[huoyaoyuan]

Made it a hint for now, not confident about touching the source generation codebase just to appease this inspection

FYI: For source generation, the official recommendation is to use records or record structs. The optimal equality operations will be generated by compiler. A supplement definition of IsExternalInit is required (use internal accessibility).

[peppy]

if it works