Rewrite the "Conditional access" section

docs/reference/groups.yml

@@ -160,25 +160,26 @@
     # Conditional access
     You can also use this in combination with the [dictionary
     constructor]($dictionary) to conditionally access global definitions. This
-    can, for instance, be useful to use new or experimental functionality (like
-    the [`target`] function) when it is available, while falling back to an
-    alternative implementation if used on an older Typst version.
+    can, for instance, be useful to use new or experimental functionality when
+    it is available, while falling back to an alternative implementation if
+    used on an older Typst version. In particular, this allows us to create
+    [polyfills](https://en.wikipedia.org/wiki/Polyfill_(programming)). It can
+    be as simple as creating an alias to prevent warning messages, for example,
+    conditionally using `pattern` in Typst version 0.12, but using `tiling` in
+    newer ones. Since function's [API](https://en.wikipedia.org/wiki/API)
+    hasn't changed, simply using the `tiling` name to refer to both will unify
+    function's usage for old and new versions.
 
     ```example
-    #let target = dictionary(std).at(
-      "target",
-      default: () => "paged",
-    )
+    #let tiling = dictionary(std).at("tiling", default: none)
+    #if tiling == none { tiling = pattern }
 
-    #context if target() == "html" [
-      HTML
-    ] else [
-      Paged
-    ]
+    ...
     ```
 
-    Make sure to use this functionality responsibly as the behavior of your code
-    can change with new Typst versions!
+    Note that creating a polyfill means that you are responsible for checking
+    that it works on older Typst versions (that support `std`). That is, if it
+    is intended for public use.
 
 - name: sys
   title: System