aria2c: fix multiple url use syntax and add checksum usage (#12250)

* aria2c: fix multiple url use syntax and add checksum usage

* Update pages/common/aria2c.md

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>

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Co-authored-by: Juri Dispan <juri.dispan@posteo.net>

pages/common/aria2c.md

@@ -16,9 +16,9 @@
 
 `aria2c --force-sequential {{false}} "{{url1 url2 ...}}"`
 
-- Download from multiple sources with each URI pointing to the same file:
+- Download the same file from different mirrors and verify the checksum of the downloaded file:
 
-`aria2c "{{url1 url2 ...}}"`
+`aria2c --checksum={{sha-256}}={{hash}} "{{url1}}" "{{url2}}" "{{urlN}}"`
 
 - Download the URIs listed in a file with a specific number of parallel downloads: