Update string literal example

Both examples were using double quotes, this change the second example to single quotes

tutorials/scripting/gdscript/gdscript_basics.rst

@@ -298,7 +298,7 @@ Literals
 +--------------------------+----------------------------------------+
 | ``3.14``, ``58.1e-10``   | Floating-point number (real)           |
 +--------------------------+----------------------------------------+
-| ``"Hello"``, ``"Hi"``    | Strings                                |
+| ``"Hello"``, ``'Hi'``    | Strings                                |
 +--------------------------+----------------------------------------+
 | ``"""Hello"""``          | Multiline string                       |
 +--------------------------+----------------------------------------+