PEP 804: Remedy a broken link to the Arch Linux mapping example (#4607)

Author: dr-carlos

peps/pep-0804.rst

@@ -780,7 +780,7 @@ They are not meant to be prescriptive, but just illustrative of how to apply the
 
 - Mappings:
 
-  - `Arch-linux <https://github.com/jaimergp/external-metadata-mappings/blob/main/data/arch-linux.mapping.json>`__.
+  - `Arch-linux <https://github.com/jaimergp/external-metadata-mappings/blob/main/data/arch.mapping.json>`__.
 
   - `Chocolatey <https://github.com/jaimergp/external-metadata-mappings/blob/main/data/chocolatey.mapping.json>`__.