Remove experimental bit on multiproc

Author: brian-brazil

README.md

@@ -380,8 +380,6 @@ return an empty list.
 
 ## Multiprocess Mode (Gunicorn)
 
-**Experimental: This feature is new and has rough edges.**
-
 Prometheus client libaries presume a threaded model, where metrics are shared
 across workers. This doesn't work so well for languages such as Python where
 it's common to have processes rather than threads to handle large workloads.
@@ -393,7 +391,7 @@ This comes with a number of limitations:
 - Custom collectors do not work (e.g. cpu and memory metrics)
 - The pushgateway cannot be used
 - Gauges cannot use the `pid` label
-- Gunicron's `preload_app` feature is not supported
+- Gunicron's `preload_app` feature are equivilents are not supported
 
 There's several steps to getting this working: