org.el (org-paste-subtree): Fix typo in docstring

* org.el (org-paste-subtree): Fix typo in docstring.

lisp/org.el

@@ -7920,7 +7920,7 @@ The entire subtree is promoted or demoted in order to match a new headline
 level.
 
 If the cursor is at the beginning of a headline, the same level as
-that headline is used to paste the tree
+that headline is used to paste the tree.
 
 If not, the new level is derived from the *visible* headings
 before and after the insertion point, and taken to be the inferior headline