Update doc/guides/feature-request-management.md

Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: mhdawson

doc/guides/feature-request-management.md

@@ -77,7 +77,7 @@ feature request in the next month, the following
 comment is added to the issue and the issue will be
 closed:
 
-```text
+```markdown
 There has been no activity on this feature request
 and it is being closed.  We value your input
 and if you feel closing this issue was not the