Small tweak to release history formatting

Author: darryllawson

release_history.txt

@@ -1,6 +1,7 @@
 1.2.0, 8 August 2019
 
-- The *notedown_lint* command now checks for a valid note title. That is, it requires that the first line of the note is a Markdown Heading 1.
+- The notedown_lint command now checks for a valid note title. That is,
+  it requires that the first line of the note is a Markdown Heading 1.
 
 
 1.1.0, 1 August 2019