Avoid different commands for intel and silicon on the Mac installation page,...

Avoid different commands for intel and silicon on the Mac installation page, as the silicon instructions work for both.

As @maerwald says here, this could be better done in the script itself, but it needs a mac person to test it.

www/index.html

@@ -32,9 +32,6 @@
 
       <div id="platform-instructions-mac" class="instructions" style="display: none;">
         <p>Run the following in your terminal (as a user other than root), then follow the onscreen instructions.</p>
-		<p>On Intel:</p>
-		<div class="command-button"><pre><span class='ghcup-command' id="ghcup-command-normal">curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh</span></pre><button class="tooltip" onclick="copyToClipboard()"><img src="copy.svg" alt="" /><span class="tooltiptext">Copy to clipboard</span></button></div>
-        <p>On Apple Silicon:</p>
 		<div class="command-button"><pre><span class='ghcup-command' id="ghcup-command-silicon">curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | arch -x86_64 /bin/bash</span></pre><button class="tooltip" onclick="copyToClipboardSilicon()"><img src="copy.svg" alt="" /><span class="tooltiptext">Copy to clipboard</span></button></div>
         <p class="other-help">If you don't like curl | sh, see <a href="https://gitlab.haskell.org/haskell/ghcup-hs#manual-install">other installation methods</a>.<br/>You appear to be running macOS. If not, <a class="default-platform-button" href="#">display all supported installers</a>.</p>
       </div>