Remove "these are denoted below" w.r.t. SIGHUP

SIGHUP support is denoted in the sections/options that support actions on SIGHUP, so with the new docs layout it's confusing to have the old statement in there. Remove in favor of the inline comments.

Fixes #2572

website/source/docs/configuration/index.html.md

@@ -32,9 +32,6 @@ telemetry {
 After the configuration is written, use the `-config` flag with `vault server`
 to specify where the configuration is.
 
-Starting with 0.5.2, limited configuration options can be changed on-the-fly by
-sending a SIGHUP to the server process. These are denoted below.
-
 ## Parameters
 
 - `storage` <tt>([StorageBackend][storage-backend]: \<required\>)</tt> –