Add a release blurb and fixup changes for 2021.2 (#12700)

Adds a release blurb and proposes some changes to the changelog and userGuide.

Author: seanbudd

user_docs/en/changes.t2t

@@ -4,21 +4,25 @@ What's New in NVDA
 %!includeconf: ../changes.t2tconf
 
 = 2021.2 =
+This release introduces preliminary Windows 11 support.
+While Windows 11 is yet to be released, this release has been tested on preview versions of Windows 11.
+This includes an important fix for Screen Curtain (see important notes).
+The COM Registration Fixing Tool can now resolve more problems when running NVDA.
+There are updates to the synthesizer eSpeak and braille translator LibLouis.
+There are also various bug fixes and improvements, notably for braille support and Windows terminals, calculator, emoji panel and clipboard history.
+
 
 == Important notes ==
-- Screen Curtain on previous releases of NVDA is no longer compatible with versions of Windows newer than Windows 10 21H2 (10.0.19044).
+Due to a change in the Windows Magnification API, Screen Curtain had to be updated to support the newest versions of Windows.
+Use NVDA 2021.2 to activate Screen Curtain with Windows 10 21H2 (10.0.19044) or later.
 This includes Windows 10 Insiders and Windows 11.
-This is due to a change in the Windows Magnification API.
-When using previous NVDA releases and Windows newer than Windows 10 21H2, screen curtain may fail to work without warning.
-To ensure security, confirm that screen curtain works properly with new or experimental versions of Windows.
-(#12491, #12684)
--
+For security purposes, when using a new version of Windows, get visual confirmation that the Screen Curtain makes the screen entirely black.
 
 
 == New Features ==
-- Support for ARIA annotations:
+- Experimental support for ARIA annotations:
   - adds a command to read a summary of details of an object with aria-details. (#12364)
-  - adds an option in advanced to report if an object has details in browse mode. (#12439) 
+  - adds an option in advanced preferences to report if an object has details in browse mode. (#12439) 
   -
 - In Windows 10 Version 1909 and later (including Windows 11), NVDA will announce suggestion count when performing searches in File Explorer. (#10341, #12628)
 - In Microsoft Word, NVDA now announces the result of indent and hanging indent shortcuts when executed. (#6269)
@@ -61,7 +65,7 @@ To ensure security, confirm that screen curtain works properly with new or exper
   - ``processPositiveStates`` and ``processNegativeStates`` have been deprecated for removal.
   -
 - On Windows 10 Version 1511 and later (including Insider Preview builds), the current Windows feature update release name is obtained from Windows Registry. (#12509)
-- Deprecated: winVersion.WIN10_RELEASE_NAME_TO_BUILDS will be removed in 2022.1, there is no direct replacement. (#12544)
+- Deprecated: ``winVersion.WIN10_RELEASE_NAME_TO_BUILDS`` will be removed in 2022.1, there is no direct replacement. (#12544)
 -
 
 

user_docs/en/userGuide.t2t

@@ -789,14 +789,15 @@ When Visual Highlight is enabled in the [vision category #VisionSettings] of the
 ++ Screen Curtain ++[VisionScreenCurtain]
 As a blind or vision impaired user, it is often not possible or necessary to see the contents of the screen.
 Furthermore, it might be hard to ensure that there isn't someone looking over your shoulder.
-For this situation, NVDA contains a feature called "screen curtain" which can be enabled to make the screen black.
+For this situation, NVDA contains a feature called "Screen Curtain" which can be enabled to make the screen black.
 
 You can enable the Screen Curtain in the [vision category #VisionSettings] of the [NVDA Settings #NVDASettings] dialog.
 
-When the screen curtain is active some tasks directly based on what appears on the screen such as performing [OCR #Win10Ocr] or taking a screenshot cannot be achieved.
+When the Screen Curtain is active some tasks directly based on what appears on the screen such as performing [OCR #Win10Ocr] or taking a screenshot cannot be achieved.
 
-To ensure security, confirm that the screen curtain works properly with new or experimental versions of Windows.
-When using NVDA releases older than 2021.2 and Windows newer than Windows 10 21H2, screen curtain may fail to work without warning.
+Due to a change in the Windows Magnification API, Screen Curtain had to be updated to support the newest versions of Windows.
+Use NVDA 2021.2 to activate Screen Curtain with Windows 10 21H2 (10.0.19044) or later.
+For security purposes, when using a new version of Windows, get visual confirmation that the Screen Curtain makes the screen entirely black.
 
 + Content Recognition +[ContentRecognition]
 When authors don't provide sufficient information for a screen reader user to determine the content of something, various tools can be used to attempt to recognize the content from an image.