[Bug] sp_doc - Need to escape links in EPs

**Describe the bug**
When testing #204  I noticed the provided extended property values were showing up as a link (`[nvarchar](4000)`) in the output. 

**To Reproduce**
Add `[nvarchar](4000)` to an extended property and run sp_doc.

**Expected behavior**
Some or all of the above characters should be escaped to prevent this from happening, similar to #185 

