patch 9.0.0118: no test for what patch 9.0.0155 fixes

Problem:    No test for what patch 9.0.0155 fixes.
Solution:   Add a test. Fix typos.  (closes #10822)
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index e4e0d66..55c2146 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -6453,7 +6453,7 @@
 	'cmdheight' is zero, the ruler is not shown.  Otherwise it is shown in
 	the last line of the screen.  If the statusline is given by
 	'statusline' (i.e. not empty), this option takes precedence over
-	'ruler' and 'rulerformat'
+	'ruler' and 'rulerformat'.
 	If the number of characters displayed is different from the number of
 	bytes in the text (e.g., for a TAB or a multibyte character), both
 	the text column (byte number) and the screen column are shown,