Fixup 'Temporary Copy restrictions' in the user guide (#15222)

#13985 introduced new restrictions for temporary copies of NVDA, preventing the add-on store from opening and preventing writing to disk.
These should be explained in the user guide

Description of user facing changes
N/A

Description of development approach
Simplified some of the structure in the user guide, including explaining what a temporary copy is.

user_docs/en/userGuide.t2t

@@ -347,9 +347,13 @@ The installed copy is also able to create a portable copy of itself at any time.
 The portable copy also has the ability to install itself on any computer at a later time.
 However, if you wish to copy NVDA onto read-only media such as a CD, you should just copy the download package.
 Running the portable version directly from read-only media is not supported at this time.
-Using the temporary copy of NVDA is also an option (e.g. for demonstration purposes), though starting NVDA in this way each time can become very time consuming.
 
-Apart from the inability to automatically start during and/or after log-on, the portable and temporary copies of NVDA also have the following restrictions:
+The [NVDA installer #StepsForRunningTheDownloadLauncher] can be used as a temporary copy of NVDA.
+Temporary copies prevent saving NVDA configuration such as settings or input gestures.
+This includes disabling usage of the [Add-on Store #AddonsManager].
+
+Portable and temporary copies of NVDA have the following restrictions:
+- The inability to automatically start during and/or after log-on.
 - The inability to interact with applications running with administrative privileges, unless of course NVDA itself has been run also with these privileges (not recommended).
 - The inability to read User Account Control (UAC) screens when trying to start an application with administrative privileges.
 - Windows 8 and later: the inability to support input from a touchscreen.