DOCS-18789 Correcting case sensitivity limitation blurb

Author: ianf-mongodb

source/includes/fact-case-sensitivity-limitation-code.rst

@@ -0,0 +1,31 @@
+
+.. example::
+
+   If the database ``salesDB`` already exists MongoDB will 
+   return an error if if you attempt to create a database named ``salesdb``. 
+
+   .. code-block:: javascript
+
+      mixedCase = db.getSiblingDB('salesDB')
+      lowerCase = db.getSiblingDB('salesdb')
+      
+      mixedCase.retail.insertOne({ "widgets": 1, "price": 50 })
+
+   The operation succeeds and :method:`~db.collection.insertOne()` implicitly
+   creates the ``SalesDB`` database.
+
+   .. code-block:: javascript
+
+      lowerCase.retail.insertOne({ "widgets": 1, "price": 50 })
+
+   The operation fails. :method:`~db.collection.insertOne()` tries to 
+   create a ``salesdb`` database and is blocked by the naming 
+   restriction. Database names must differ on more than just case.
+
+   .. code-block:: javascript
+
+       lowerCase.retail.find()
+
+   This operation does not return any results because the database names are case
+   sensitive. There is no error because :method:`~db.collection.find()` doesn't
+   implicitly create a new database.

source/reference/limits.txt

@@ -36,8 +36,11 @@ Naming Restrictions
 
 .. limit:: Database Name Case Sensitivity
 
-   Since database names are case *insensitive* in MongoDB, database
-   names cannot differ only by the case of the characters.
+   Database names are case-sensitive in MongoDB. They also have an 
+   additional restriction, case cannot be the only difference between
+   database names. 
+
+   .. include:: /includes/fact-case-sensitivity-limitation-code.rst
 
 .. limit:: Restrictions on Database Names for Windows