Fix the duplicate glyphs in Inheritance margin

[Cosifne]

Fix: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1988154/
Currently, you might find there are duplicate glyphs in inheritance margin like:

(There are three controls created in the canvas, all of them are same)

Reason:
Our tagger infra has switched to a three-tagger stucture.
Tagger 1 -> Tag the [visible region + 10 line, visible region - 10 line]
Tagger 2 -> Tag the [visible region + 10 line, visible region + 100 line]
Tagger 3 -> Tag the [visible region - 100 line, visible region - 10 line]

This change causes problem here

So computing the symbol to tag, inheritance margin service would call root.DescendantNodes(spanToSearch) to find all the nodes intersect with spanToSearch.
So suppose you have a class, and the visible region is around class A

//1k lines comments
class A
{
// 1k lines body
}

Tagger 1 would tag class A. (Because the spanToSearch is the visible span)
Tagger 2 would also tag class A, because the top lines span also intersects with class A
Tagger 3 would also tag class A, because the empty body span also intersects with class A

The solution is to only create the tag when spanToSearch contains the member's identifier.

[Cosifne]

This test is modified a little bit.
The prev test is asserting that no inheritanceMargin tag should be created for special C# methods. (e.g. constructor/deconsctructor/operator)

So the assertion is just assert one tag is created for the type (class Bar1 here)

It only chooses to search the memberDeclaration region so only tags for Bar1 would be created.

However, after the change, we would only return the tag within the search span. So expand the SearchAreaTag area here to include class Bar1
No real change here.

[DoctorKrolic]

Fixes #73615?

[Cosifne]

Fixes #73615?

Yes it should fix the problem