Minor bug fix to update heading

Author: abrennan89

serverless/discover/serverless-functions-about.adoc

@@ -12,7 +12,7 @@ toc::[]
 include::snippets/technology-preview.adoc[leveloffset=+2]
 
 [id="serverless-functions-about-runtimes"]
-== Supported runtimes
+== Included runtimes
 
 {FunctionsProductName} provides templates that can be used to create basic functions for the following runtimes: