make IRShow.method_name inferrable

[KristofferC]

4 methods pushes it over the limit.

Seems to have the same effect as #49605.

Now:

julia> code_warntype(Base.IRShow.method_name, Tuple{Core.LineInfoNode})

MethodInstance for Base.IRShow.method_name(::Core.LineInfoNode)
  from method_name(m::Core.LineInfoNode) @ Base.IRShow compiler/ssair/show.jl:185
Arguments
  #self#::Core.Const(Base.IRShow.method_name)
  m::Core.LineInfoNode
Body::Symbol
1 ─      nothing
│   %2 = Base.getproperty(m, :method)::Any
│   %3 = Base.IRShow.normalize_method_name(%2)::Symbol
└──      return %3

[vtjnash]

This seems somewhat less good code structure. But we also should be using === to compare Symbols not ==

[KristofferC]

This seems somewhat less good code structure.

Yes and if the results where equivalent I would have kept the previous one.

[vtjnash]

I think file is also required (inferably) to be a Symbol?

[vtjnash]

This seems somewhat less good code structure.

Yes and if the results where equivalent I would have kept the previous one.

Touché. Does the === change fix this and/or should we add a type assert for Symbol in the call wrapper of this that seems may be present already?

[KristofferC]

The issue is already fixed by making the function inferable, but for consistency it is indeed good to fix so that all symbol comparisons are made with ===