Fix to @set reducing errors during building using strings without using quotes.

src/commands/default/building.py

@@ -1232,7 +1232,7 @@ class CmdSetAttribute(ObjManipCommand):
             # Use literal_eval to parse python structure exactly.
             try:
                 return _LITERAL_EVAL(strobj)
-            except ValueError:
+            except SyntaxError:
                 # treat as string
                 string = "{RNote: Value was converted to string. If you don't want this, "
                 string += "use proper Python syntax, like enclosing strings in quotes.{n"