Fix typo in docs

Fixes a typo from #6477

doc/05-repositories.md

@@ -658,7 +658,7 @@ You can disable the default Packagist.org repository by adding this to your
 You can disable Packagist.org globally by using the global config flag:
 
 ```
-composer confg -g repo.packagist false
+composer config -g repo.packagist false
 ```
 
 ← [Schema](04-schema.md)  |  [Config](06-config.md) →