downloads/mac: replace Xcode with Command Line Tools

Apples Xcode Command Line Tools provides git without the full Xcode IDE.
It can also easily be installed via `xcode-select --install`.

Author: kerhac

content/install/mac.html

@@ -24,8 +24,11 @@ <h3>MacPorts</h3>
   <p>Install <a href="https://www.macports.org">MacPorts</a> if you don't already have it, then:<br>
   <code>$ sudo port install git</code></p>
 
-  <h3>Xcode</h3>
-  <p>Apple ships a binary package of Git with <a href="https://developer.apple.com/xcode/">Xcode</a>.</p>
+  <h3>Xcode Command Line Tools</h3>
+  <p>Apple ships a binary package of Git with <a
+  href="https://developer.apple.com/xcode/resources/">Xcode Command Line
+  Tools</a>. You can install this via:<br>
+  <code>$ xcode-select --install</code></p>
 
   <h3>Installing git-gui</h3>
   <p>If you would like to install <a href="https://git-scm.com/docs/git-gui/">git-gui</a> and <a href="https://git-scm.com/docs/gitk/">gitk</a>,