doc: Sync classref with current source

modules/opensimplex/doc_classes/OpenSimplexNoise.xml

@@ -37,6 +37,14 @@
 				Generate a noise image with the requested [code]width[/code] and [code]height[/code], based on the current noise parameters.
 			</description>
 		</method>
+		<method name="get_noise_1d">
+			<return type="float">
+			</return>
+			<argument index="0" name="x" type="float">
+			</argument>
+			<description>
+			</description>
+		</method>
 		<method name="get_noise_2d">
 			<return type="float">
 			</return>