minor #16412 php.net callback documentation link changed (fzsys)

This PR was submitted for the 6.0 branch but it was merged into the 4.4 branch instead.

Discussion
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php.net callback documentation link changed

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7634581 php.net callback documentation link changed

Author: javiereguiluz

create_framework/templating.rst

@@ -178,5 +178,5 @@ As always, you can decide to stop here and use the framework as is; it's
 probably all you need to create simple websites like those fancy one-page
 `websites`_ and hopefully a few others.
 
-.. _`callbacks`: https://www.php.net/callback#language.types.callback
+.. _`callbacks`: https://www.php.net/manual/en/language.types.callable.php
 .. _`websites`: https://kottke.org/08/02/single-serving-sites