patch 8.1.1308: the Normal highlight is not defined when compiled with GUI

Problem:    The Normal highlight is not defined when compiled with GUI.
Solution:   Always define Normal. (Christian Brabandt, closes #4072)
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index c3ce75c..1eca1c5 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -5002,6 +5002,8 @@
 		text (see 'conceallevel')
 							*hl-Cursor*
 Cursor		the character under the cursor
+lCursor		the character under the cursor when |language-mapping|
+		is used (see 'guicursor')
 							*hl-CursorIM*
 CursorIM	like Cursor, but used when in IME mode |CursorIM|
 							*hl-CursorColumn*