Fix JS error due to missing element

The conditions to show the explanation for m1 support are inconsistent.
The one that triggers the explanation uses version<=? and
the one that creates the explanation uses version<?.
Therefore, when the version is exactly version-before-m1-support,
it attempts to show the explanation that doesn't exist.

This PR makes the adjustment to make the conditions consistent.
Based on the name `version-before-m1-support`,
version<? seems to be the right one to use.

Fixes #336

download/download-pages.rkt

@@ -792,7 +792,7 @@ var property = null;
            }
            null)
 
-      @(if (version<=? version-before-m1-support version)
+      @(if (version<? version-before-m1-support version)
            @list{
                  @; showWhen('m1_mac_explain', platform === 'x86_64-macosx');
                  showWhen('intel_mac_explain', platform === 'aarch64-macosx');