Doc: Add info on how to install debug libraries

This commit adds information on how to install the debug libraries in
addition to release libraries when using -debug-and-release
configuration option on Windows.

Fixes: QTBUG-138795
Fixes: QTBUG-115206
Pick-to: 6.10
Change-Id: I3c1c0bd1c86988285af2c3cba74add01ca9dfefb
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

doc/src/platforms/windows.qdoc

@@ -1091,18 +1091,28 @@
 
         \badcode
         cmake --build . --parallel
+        # or
+        ninja
         \endcode
 
         Period after \c {--build} means current folder.
 
         After building, you need to install the libraries and tools in the desired path
-        (unless you enabled a \l {Developer Builds}
-        {developer build}:
+        (unless you enabled a \l {Developer Builds}{developer build}):
 
         \badcode
         cmake --install .
+        # or
+        ninja install
         \endcode
 
+        \note \b {For CMake version < 4.0.} The \c {cmake --install .} command
+        installs only the release versions of the libraries and tools even if
+        you build both debug and release libraries. To install both the debug
+        and release libraries, use \c {ninja install}. You can also run both the
+        \c {cmake --install . --config Debug} and
+        \c {cmake --install . --config Release} commands.
+
     \section1 Step 4: Building Your Application
 
         After Qt is installed, you can start building applications with it.