chore: clean up structProjCases pass (#8455)

Author: zwarich

src/Lean/Compiler/LCNF/StructProjCases.lean

@@ -31,11 +31,11 @@ def mkFieldParamsForCtorType (e : Expr) (numParams : Nat): CompilerM (Array Para
     | _ => return params
   loop #[] e numParams
 
-structure StructProjState where
+structure State where
   projMap : Std.HashMap FVarId (Array FVarId) := {}
   fvarMap : Std.HashMap FVarId FVarId := {}
 
-abbrev M := StateRefT StructProjState CompilerM
+abbrev M := StateRefT State CompilerM
 
 def M.run (x : M α) : CompilerM α := do
   x.run' {}
@@ -128,4 +128,6 @@ end StructProjCases
 def structProjCases : Pass :=
   .mkPerDeclaration `structProjCases (StructProjCases.visitDecl · |>.run) .mono
 
+builtin_initialize registerTraceClass `Compiler.structProjCases (inherited := true)
+
 end Lean.Compiler.LCNF