make chapter name reflect file name

Personally I think this makes more sense anyway.

docs/SUMMARY.md

@@ -4,7 +4,7 @@ # Summary
 - [Differences from upstream Conduit](differences.md)
 
 - [Example configuration](configuration.md)
-- [Deployment options](deploying.md)
+- [Deploying](deploying.md)
     - [Generic](deploying/generic.md)
     - [Debian](deploying/debian.md)
     - [Docker](deploying/docker.md)

docs/deploying.md

-# Deployment options
+# Deploying
 
 This chapter describes various ways to deploy Conduit.