Use CategoryChannelResolvable for parent setting

[almostSouji]

Is your feature request related to a problem? Please describe.
During the setup of #5507 it came to attention that categories are currently typed as ChannelResolvable whenever we ask for a potential parent channel

• ⚠️ requires feat(Guild): setChannelPositions parent, lockPermissions keys #5507, typedef/doc is introduced there, needs to be applied across other instances of parent* functionality

Describe the ideal solution
The type and documentation could be more specific by introducing a CategoryResolvable type

Describe alternatives you've considered
n/a

Additional context
n/a

[polypixeldev]

I also think that a CategoryResolvable type would help work with categories since it is a little confusing having them as a channel This feature would definitely help clarify some things.