Clean up macros (#14959)

tests/macros/tmemit.nim

@@ -1,6 +1,5 @@
 discard """
   output: '''
-HELLO WORLD
 c_func
 12
 '''
@@ -8,8 +7,6 @@ c_func
 
 import macros, strutils
 
-emit("echo " & '"' & "hello world".toUpperAscii & '"')
-
 # bug #1025
 
 macro foo(icname): untyped =

tests/showoff/tformatopt.nim

@@ -37,7 +37,7 @@ macro optFormat{`%`(f, a)}(f: string{lit}, a: openArray[string]): untyped =
   result = newNimNode(nnkBracket)
   let f = f.strVal
   formatImpl(newLit)
-  result = nestList(!"&", result)
+  result = nestList(newIdentNode("&"), result)
 
 template optAdd1{x = y; add(x, z)}(x, y, z: string) =
   x = y & z

tests/usingstmt/tusingstatement.nim

@@ -38,7 +38,7 @@ macro autoClose(args: varargs[untyped]): untyped =
       varAssignment.add(varValue)
       variables.add(varAssignment)
 
-      closingCalls.add(newCall(!"close", varName))
+      closingCalls.add(newCall(newIdentNode("close"), varName))
     else:
       error "Using statement: Unexpected expression. Got " &
         $args[i].kind & " instead of assignment."