Update WHATWG links to use HTTPS

Extracted this out of #5649

This commit was created with the following commands:

```
find . -iname "*.webidl" -type f -print0 | xargs -0 sed -i '' 's/http:\(.*\)whatwg.org/https:\1whatwg.org/g'
```

```
find . -iname "*.rs" -type f -print0 | xargs -0 sed -i '' 's/http:\(.*\)whatwg.org/https:\1whatwg.org/g'
```

components/script/dom/range.rs

@@ -37,7 +37,7 @@ impl Range {
 }
 
 impl<'a> RangeMethods for JSRef<'a, Range> {
-    /// http://dom.spec.whatwg.org/#dom-range-detach
+    /// https://dom.spec.whatwg.org/#dom-range-detach
     fn Detach(self) {
         // This method intentionally left blank.
     }