(DOCSP-43739) Standardize FCV (#372)

Author: elyse-mdb

source/changelog.txt

@@ -455,7 +455,7 @@ v2.0.0
   - ``upgradeState``
 
   To obtain version information, see the :ref:`feature compatibility
-  version (fcv) <view-fcv>`.
+  version (FCV) <view-fcv>`.
 
 - Removes support for :ref:`Free Monitoring <free-monitoring-mongodb>`
   helper functions: