Merge branch 'patch-18' of https://github.com/PiJoCoder/sql-docs-pr into 20201026-pr-17683

Author: MikeRayMSFT

docs/t-sql/database-console-commands/dbcc-freesystemcache-transact-sql.md

@@ -47,7 +47,7 @@ DBCC FREESYSTEMCACHE
 ## Arguments
 ( 'ALL' [,_pool\_name_ ] )  
 ALL specifies all supported caches.  
-_pool\_name_ specifies a Resource Governor pool cache. Only entries associated with this pool are freed.  
+_pool\_name_ specifies a Resource Governor pool cache. Only entries associated with this pool are freed.  The pools names that can be specified as parameters here can be found from `select name from sys.dm_os_memory_clerks`. Most, but not all, caches can be individually freed using this command.
 
 MARK_IN_USE_FOR_REMOVAL  
 Asynchronously frees currently used entries from their respective caches after they're unused. After the DBCC FREESYSTEMCACHE WITH MARK_IN_USE_FOR_REMOVAL runs, new entries created in the cache aren't affected.