Prefer using https://www.wxwidgets.org/downloads/ download link

This is more user-friendly than GitHub links with their tons of files.

Also use the recently added #vX.Y.Z_msw anchor to link directly to MSW
binaries downloads from the corresponding file.

Closes https://github.com/wxWidgets/wxWidgets/pull/1820

docs/doxygen/mainpages/introduction.h

@@ -111,13 +111,12 @@ configurations but at least 1GB and possibly more is required.
 
 @section page_introduction_where Where to get wxWidgets and support for it
 
-The download links can be found at https://www.wxwidgets.org. The primary
-download location is https://github.com/wxWidgets/wxWidgets/releases/latest.
+The download links can be found at https://www.wxwidgets.org/downloads/.
 Additionally, the latest version can always be retrieved from our version
 control system using Git (https://github.com/wxWidgets/wxWidgets).
 
-wxWidgets documentation that you are reading is also available online at
-https://docs.wxwidgets.org/trunk/ and please also visit our wiki at
+The latest version of wxWidgets documentation that you are reading is available
+online at https://docs.wxwidgets.org/trunk/ and please also see
 https://wiki.wxwidgets.org/ for user-contributed contents.
 
 And if you have any questions, you can join wxWidgets community using

docs/msw/binaries.md

@@ -30,7 +30,7 @@ e.g. for 32-bit MSVS 2017 development you need
 
 All binaries are available at:
 
-https://github.com/wxWidgets/wxWidgets/releases/v3.1.3
+https://www.wxwidgets.org/downloads#v3.1.3_msw
 
 Once you have the files you need, unzip all of them into the same directory, for
 example `c:\wx\3.1.3`. You should have only include and lib subdirectories under

docs/publicity/announce.txt

@@ -5,7 +5,7 @@ cross-platform applications in C++.
 wxWidgets 3.1.3 is the latest release in the 3.1 development
 branch and is now available at
 
-    https://github.com/wxWidgets/wxWidgets/releases/tag/v3.1.3
+    https://www.wxwidgets.org/downloads/
 
 Compared to the stable 3.0.x series, this version brings many
 improvements and even more bug fixes, please see the change log

docs/readme.txt

@@ -21,6 +21,10 @@ Documentation is available online at:
 wxWidgets sources and binaries for the selected platforms are available for
 download from:
 
+* https://www.wxwidgets.org/downloads/
+
+or, for a more more permanent but less convenient to use link, from
+
 * https://github.com/wxWidgets/wxWidgets/releases/tag/v3.1.4/