Clarify library installation instructions for macOS

Don't explain how to install the library first only to say that it
shouldn't be done afterwards.

Also separate the discussion of installing and distributing the
libraries.

Closes #16316.

docs/osx/install.md

@@ -3,7 +3,7 @@ wxWidgets for OS X installation        {#plat_osx_install}
 
 [TOC]
 
-wxWidgets can be compiled using Apple's Cocoa library.
+wxWidgets can be compiled using Apple's Cocoa toolkit.
 
 Most OS X developers should start by downloading and installing Xcode
 from the App Store.  It is a free IDE from Apple that provides
@@ -45,6 +45,11 @@ Advanced topics                        {#osx_advanced}
 Installing library                     {#osx_install}
 ------------------
 
+It is rarely desirable to install non-Apple software into system directories,
+so the recommended way of using wxWidgets under macOS is to skip the `make
+install` step and simply use the full path to `wx-config` under the build
+directory when building application using the library.
+
 If you want to install the library into the system directories you'll need
 to do this as root.  The accepted way of running commands as root is to
 use the built-in sudo mechanism.  First of all, you must be using an
@@ -53,18 +58,15 @@ account marked as a "Computer Administrator".  Then
     sudo make install
     type \<YOUR OWN PASSWORD\>
 
-Note that while using this method is okay for development, it is not
-recommended that you require endusers to install wxWidgets into their
-system directories in order to use your program.  One way to avoid this
-is to configure wxWidgets with --disable-shared.  Another way to avoid
-it is to make a framework for wxWidgets.  Making frameworks is beyond
-the scope of this document.
-
-**Note:**
-It is rarely desirable to install non-Apple software into system directories.
-By configuring the library with --disable-shared and using the full path
-to wx-config with the --in-place option you can avoid installing the library.
+Distributing applications using wxWidgets
+-----------------------------------------
 
+If you build wxWidgets as static libraries, i.e. pass `--disable-shared` option
+to configure, you don't need to do anything special to distribute them, as all
+the required code is linked into your application itself. When using shared
+libraries (which is the default), you need to copy the libraries into your
+application bundle and change their paths using `install_name_tool` so that
+they are loaded from their new locations.
 
 Apple Developer Tools: Xcode           {#osx_xcode}
 ----------------------------