patch 8.1.2029: cannot control 'cursorline' highlighting well

Problem:    Cannot control 'cursorline' highlighting well.
Solution:   Add "screenline". (Christian Brabandt, closes #4933)
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 0c8589f..9fa2bfb 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2468,17 +2468,24 @@
 
 
 						*'cursorlineopt'* *'culopt'*
-'cursorlineopt' 'culopt' string (default: "both")
+'cursorlineopt' 'culopt' string (default: "number,line")
 			local to window
 			{not in Vi}
 			{not available when compiled without the |+syntax|
 			feature}
-	Settings for how 'cursorline' is displayed.  Valid values:
-	    "line"	Highlight the text line of the cursor with
+	Comma separated list of settings for how 'cursorline' is displayed.
+	Valid values:
+	"line"		Highlight the text line of the cursor with
 			CursorLine |hl-CursorLine|.
-	    "number"	Highlight the line number of the cursor with
+	"screenline"	Highlight only the screen line of the cursor with
+			CursorLine |hl-CursorLine|.
+	"number"	Highlight the line number of the cursor with
 			CursorLineNr |hl-CursorLineNr|.
-	    "both"	Highlight as both "line" and "number" are set.
+
+	Special value:
+	"both"		Alias for the values "line,number".
+
+	"line" and "screenline" cannot be used together.
 
 
 						*'debug'*