clarify the slicing example (#36842) (#36847)

As stated by fellow contributors, update the slicing example

Resolves:
Related: #36625
Signed-off-by: Daniel Andrei Minca <mandrei17@gmail.com>
(cherry picked from commit 8362ddd107)

docs/docsite/rst/user_guide/intro_patterns.rst

@@ -81,9 +81,10 @@ You can refer to hosts within the group by adding a subscript to the group name:
 
     webservers[0]       # == cobweb
     webservers[-1]      # == weber
-    webservers[0:1]     # == webservers[0],webservers[1]
+    webservers[0:2]     # == webservers[0],webservers[1]
                         # == cobweb,webbing
     webservers[1:]      # == webbing,weber
+    webservers[:3]      # == cobweb,webbing,weber
 
 Most people don't specify patterns as regular expressions, but you can.  Just start the pattern with a '~'::