docs: Remove tagprefix from Classic example

The Classic GitFlow example in gitflow-config.5.md still showed
tagprefix = v for release and hotfix branches, inconsistent with
the default empty tag prefix change. Remove these lines since
empty tag prefix is now the default.

Author: alexrinass

docs/gitflow-config.5.md

@@ -223,16 +223,14 @@ These are operational settings that adjust command behavior. Some can override L
     upstreamstrategy = merge
     downstreamstrategy = merge
     tag = true
-    tagprefix = v
-    
+
 [gitflow "branch.hotfix"]
     type = topic
     parent = main
     prefix = hotfix/
     upstreamstrategy = merge
     downstreamstrategy = merge
     tag = true
-    tagprefix = v
 ```
 
 ### GitHub Flow