Fix spellings (#12277) [backport]

tests/macros/tmacro3.nim

@@ -18,7 +18,7 @@ test:
 
 macro test2*(a: untyped): untyped =
   proc testproc(recurse: int) =
-    echo "Thats weird"
+    echo "That's weird"
     var o : NimNode = nil
     echo "  no its not!"
     o = newNimNode(nnkNone)

tests/macros/ttemplatesymbols.nim

@@ -122,7 +122,7 @@ template overloadedTemplate(x: string) =
 """
 
 inspectUntyped bindSym("overloadedTemplate"), """bindSym("overloadedTemplate")"""
-  # binSym is active only in the presense of `typed` params.
+  # binSym is active only in the presence of `typed` params.
   # `untyped` params still get the raw AST
 
 inspectSymbol normalProc, """