Clarify store_string vs store_line.

While the behavior can be implied from the name, it seems worth stating
it explicitly.

doc/classes/File.xml

@@ -399,8 +399,7 @@
 			<argument index="0" name="line" type="String">
 			</argument>
 			<description>
-				Stores the given [String] as a line in the file.
-				Text will be encoded as UTF-8.
+				Appends [code]line[/code] to the file followed by a line return character ([code]\n[/code]), encoding the text as UTF-8.
 			</description>
 		</method>
 		<method name="store_pascal_string">
@@ -428,8 +427,7 @@
 			<argument index="0" name="string" type="String">
 			</argument>
 			<description>
-				Stores the given [String] in the file.
-				Text will be encoded as UTF-8.
+				Appends [code]string[/code] to the file without a line return, encoding the text as UTF-8.
 			</description>
 		</method>
 		<method name="store_var">