Correct the description of #deleteArchivedReposAfter

Change-Id: I985c1a55415126e00e231420c36740cd46ca61e2
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 4b5f6f2..fd1c01e 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -85,7 +85,7 @@
 	By default `$site_path/data/delete-project`.
 
 plugin.@PLUGIN@.deleteArchivedReposAfter
-:	The time duration for the git repository to be archived.
+:	The time duration after which archived git repositories are deleted.
 
 	The following suffixes are supported to define the time unit:\n
 		1. d, day, days\n