Fix structure of About files

Author: sdwheeler

reference/5.1/Microsoft.PowerShell.Core/About/about_Environment_Variables.md

@@ -25,8 +25,6 @@ programs. PowerShell creates the following environment variables:
 For full descriptions of these variables, see the
 [PowerShell environment variables][03] of this article.
 
-## LONG DESCRIPTION
-
 PowerShell can access and manage environment variables in any of the supported
 operating system platforms. The PowerShell Environment provider lets you get,
 add, change, clear, and delete environment variables in the current console.