Merge symbol advanced "buffer extents" and "buffer settings" options

[DelazJ]

Feature description

#58228 introduced in 3.40 ability to add buffer to marker symbols.
#59630 is introducing (in 3.42) ability to set an extent buffer per symbol.
Both features are available through the "Advanced" drop down menu of a symbol layer, opening a dedicated dialog when you click on the entry

I know these are two separate features but can we consider merging both in a single "Buffer settings" entry? I find it puzzling to have two entries for buffer, there.

@nyalldawson @JuhoErvasti ?

Additional context

No response

[nyalldawson]

They both do COMPLETELY different things. One is a visible buffer akin to label buffers, the other is about filtering feature. I think the second should be renamed if there's confusion.

[baswein]

I also think this might cause some confusion with my students. Buffer is how we are getting the expanded extent but the larger extent is the important part.

Ideas for Extent Buffer...:
Render Inclusion Extent...
Feature Inclusion Distance...
Feature Render Buffer...
Map Extent Buffer...
Render Extent...

Ideas for Buffer Settings...:
Marker Buffer...
Symbol Halo...

[JuhoErvasti]

In my opinion it doesn't make sense to group them in the same menu since they do entirely different things, but I think that renaming the extent buffer to something else is a good idea if it causes confusion.

One point about @baswein's suggestions, I think if the name is to be changed the new name should convey (as some of the suggestions do) that it is specifically a buffer to the existing map extent.