Add file extension to Gedit syntax highlighting template
You can add file extensions in the html syntax coloring scheme by editing html.lang in
/usr/share/gtksourceview-2.0/language-specs/
as a super user. So say you want to add HTML syntax highlighting to cfm files, you'd change this
<property name="globs">*.html;*.htm</property>
(default html.lang) into this
<property name="globs">*.html;*.htm;*.cfm</property>