fix: lsp struct rename/reference difference

[asterite]

Description

Problem

Resolves #5412

Summary

When a function parameter is self and it refers to a struct type, that variable is linked to that type (through a synthetic "Self" type):

struct Foo {
}

impl Foo {
  fn foo(self) { // <-- here
  }
}

Then, when renaming Foo, those self occurrences were incorrectly renamed. To fix that, in this PR we don't track these synthetic Self types in the reference graph.

The second thing here is that when using Self to refer to a struct type, that Self was also incorrectly renamed. To fix this we now track whether a reference to a type came from Self or from the actual struct name. Then we don't rename these Self references.

Note that we still keep these Self references in order for "find all references" to return them (this is similar to how rust-analyzer works).

lsp_rename_struct_self_Self.mov

Additional Context

None.

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.