org-tempo: Fix docstring

* lisp/org-tempo.el (org-tempo-keywords-alist): Fix docstring.

lisp/org-tempo.el

@@ -63,7 +63,7 @@
 This is an alist of KEY characters and corresponding KEYWORDS,
 just like `org-structure-template-alist'.  The tempo snippet
 \"<KEY\" will be expanded using the KEYWORD value.  For example
-\"<l\" at the beginning of a line is expanded to \"#+latex:\".
+\"<L\" at the beginning of a line is expanded to \"#+latex:\".
 
 Do not use \"I\" as a KEY, as it it reserved for expanding
 \"#+include\"."