Change cat shapshots docs

Author: Andrey Ershov

docs/reference/cat/snapshots.asciidoc

@@ -1,7 +1,8 @@
 [[cat-snapshots]]
-== Cat single repository snapshots
+== cat snapshots
 
-The `snapshots` command shows all snapshots that belong to a specific repository.
+The `snapshots` command shows all snapshots that belong to a specific repository
+or multiple repositories.
 To find a list of available repositories to query, the command `/_cat/repositories` can be used.
 Querying the snapshots of a repository named `repo1` then looks as follows.
 
@@ -33,7 +34,6 @@ Start and stop timestamps are available in two formats.
 The `HH:MM:SS` output is simply for quick human consumption.
 The epoch time retains more information, including date, and is machine sortable if the snapshot process spans days.
 
-== Cat multiple repositories snapshots
 It is also possible to get the list of snapshots from multiple repositories.
 Here are some examples: