Shorten ReadMe entry for Section Number plugin

Readme.rst

@@ -180,7 +180,7 @@ Representative image      Extracts a representative image (i.e, featured image)
 
 RMD Reader                Create posts via knitr RMarkdown files
 
-Section number            Adds section number to the article's context, in the form of `2.3.3` Sections are indicated by `<h1>-<h6>` in the parsed html format.
+Section number            Adds section numbers for article headers, in the form of ``2.3.3``
 
 Share post                Creates share URLs of article