Update to inclusive language - roles

Author: Chris Erdmann

_includes/lc/intro.html

@@ -1,6 +1,6 @@
 <p>
   <a href="{{site.lc_site}}">Library Carpentry</a>
-  is made by librarians, for librarians to help you:
+  is made by people working in library- and information-related roles to help you:
 </p>
 <ul>
   <li>automate repetitive, boring, error-prone tasks</li>