Pow method doc fix

(cherry picked from commit 4fd20015f35135e6a4e8e67fc8e9e1921196bef6)

modules/gdscript/doc_classes/@GDScript.xml

@@ -780,7 +780,7 @@
 			<argument index="1" name="exp" type="float">
 			</argument>
 			<description>
-				Returns the result of [code]x[/code] raised to the power of [code]y[/code].
+				Returns the result of [code]base[/code] raised to the power of [code]exp[/code].
 				[codeblock]
 				pow(2, 5) # Returns 32.0
 				[/codeblock]