Remove unused codes

Author: StevenWong12

Sources/SwiftParser/SyntaxUtils.swift

@@ -87,20 +87,6 @@ extension RawUnexpectedNodesSyntax {
   init?<T1: UnexpectedNodesCombinable, T2: UnexpectedNodesCombinable, T3: UnexpectedNodesCombinable>(combining syntax1: T1, _ syntax2: T2, _ syntax3: T3, arena: __shared SyntaxArena) {
     self.init(syntax1.elements + syntax2.elements + syntax3.elements, arena: arena)
   }
-
-  init?<T1: UnexpectedNodesCombinable, T2: UnexpectedNodesCombinable>(combining optionalSyntax1: T1?, _ optionalSyntax2: T2?, arena: __shared SyntaxArena) {
-    if let syntax1 = optionalSyntax1,
-      let syntax2 = optionalSyntax2
-    {
-      self.init(syntax1.elements + syntax2.elements, arena: arena)
-    } else if let syntax1 = optionalSyntax1 {
-      self.init(syntax1.elements, arena: arena)
-    } else if let syntax2 = optionalSyntax2 {
-      self.init(syntax2.elements, arena: arena)
-    } else {
-      return nil
-    }
-  }
 }
 
 // MARK: - Misc