Merge pull request #81639 from MJacred/is_letter

Add `is_valid_letter()` to `TextServer`

doc/classes/TextServer.xml

@@ -1103,6 +1103,13 @@
 				- May contain Unicode characters of class XID_Continue in the other positions.
 			</description>
 		</method>
+		<method name="is_valid_letter" qualifiers="const">
+			<return type="bool" />
+			<param index="0" name="unicode" type="int" />
+			<description>
+				Returns [code]true[/code] if the given code point is a valid letter, i.e. it belongs to the Unicode category "L".
+			</description>
+		</method>
 		<method name="load_support_data">
 			<return type="bool" />
 			<param index="0" name="filename" type="String" />