cgitrc.5.txt: Fix documentation of the snapshot mask

Mention that the snapshot setting only specifies the formats that links
are generated for and not the set of formats that are accessible via
HTTP.

Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>

cgitrc.5.txt

@@ -390,10 +390,10 @@ side-by-side-diffs::
 	default. Default value: "0".
 
 snapshots::
-	Text which specifies the default set of snapshot formats generated by
-	cgit. The value is a space-separated list of zero or more of the
-	values "tar", "tar.gz", "tar.bz2", "tar.xz" and "zip". Default value:
-	none.
+	Text which specifies the default set of snapshot formats that cgit
+	generates links for. The value is a space-separated list of zero or
+	more of the values "tar", "tar.gz", "tar.bz2", "tar.xz" and "zip".
+	Default value: none.
 
 source-filter::
 	Specifies a command which will be invoked to format plaintext blobs
@@ -538,8 +538,9 @@ repo.readme::
 	file. Default value: <readme>.
 
 repo.snapshots::
-	A mask of allowed snapshot-formats for this repo, restricted by the
-	"snapshots" global setting. Default value: <snapshots>.
+	A mask of snapshot formats for this repo that cgit generates links for,
+	restricted by the global "snapshots" setting. Default value:
+	<snapshots>.
 
 repo.section::
 	Override the current section name for this repository. Default value: