DOCSP-5744:Update Performance Tab Intro to reflect it is not availabl… (#143)

* DOCSP-5744:Update Performance Tab Intro to reflect it is not available in Community Edition

* DOCS-5744 Fixed typo pointed out by reviewer

Author: tahiyachowdhury

source/instance.txt

@@ -47,6 +47,7 @@ a database, see :doc:`Databases </databases>`.
 
 .. _performance-tab-home:
 
+
 Performance Tab
 ---------------
 
@@ -60,6 +61,11 @@ performance statistics and graphs, showing insights such as:
 For more information about the :guilabel:`Performance` tab, see
 :doc:`Performance </performance>`.
 
+.. note::
+
+   The :guilabel:`Performance` tab is not available in Compass Community Edition.
+
+
 .. class:: hidden
 
    .. toctree::