docs(concepts): mention PEP 625 (#7189)

## Summary

Follow-up to
#7168 (comment).

docs/concepts/resolution.md

@@ -298,9 +298,10 @@ as if they do not exist.
 
 ## Source distribution
 
-Most packages publish their source distributions as gzip tarball (`.tar.gz`) or zip (`.zip`)
-archives. While less common, other formats are also supported when reading and extracting source
-distributions:
+[PEP 625](https://peps.python.org/pep-0625/) specifies that packages must distribute source
+distributions as gzip tarball (`.tar.gz`) archives. Prior to this specification, other archive
+formats, which need to be supported for backward compatibility, were also allowed. uv supports
+reading and extracting archives in the following formats:
 
 - bzip2 tarball (`.tar.bz2`)
 - gzip tarball (`.tar.gz`)