networksetup, port, xcode-select, xcodebuild: add more information links (#7754)

* port: more info
* xcodebuild: more info
* xcode-select: more info
* networksetup: more info

pages/osx/networksetup.md

@@ -1,6 +1,7 @@
 # networksetup
 
 > Configuration tool for Network System Preferences.
+> More information: <https://support.apple.com/guide/remote-desktop/about-networksetup-apdd0c5a2d5/mac>.
 
 - List available network service providers (Ethernet, Wi-Fi, Bluetooth, etc):
 

pages/osx/port.md

@@ -1,6 +1,7 @@
 # port
 
 > Package manager for macOS.
+> More information: <https://www.macports.org>.
 
 - Search for a package:
 

pages/osx/xcode-select.md

@@ -2,6 +2,7 @@
 
 > Switch between different versions of Xcode and the included developer tools.
 > Also used to update the path to Xcode if it is moved after installation.
+> More information: <https://developer.apple.com/library/archive/technotes/tn2339/_index.html>.
 
 - Install Xcode's command-line tools:
 

pages/osx/xcodebuild.md

@@ -1,6 +1,7 @@
 # xcodebuild
 
 > Build Xcode projects.
+> More information: <https://developer.apple.com/library/archive/technotes/tn2339/_index.html>.
 
 - Build workspace: