Update awful.rules tag-related examples

Fixes: https://github.com/awesomeWM/awesome/issues/799
Signed-off-by: Uli Schlachter <psychon@znc.in>

awesomerc.lua

@@ -459,9 +459,9 @@ awful.rules.rules = {
         }
       }, properties = { floating = true }},
 
-    -- Set Firefox to always map on tags number 2 of screen 1.
+    -- Set Firefox to always map on the tag named "2" on screen 1.
     -- { rule = { class = "Firefox" },
-    --   properties = { tag = tags[1][2] } },
+    --   properties = { screen = 1, tag = "2" } },
 }
 -- }}}
 

lib/awful/rules.lua

@@ -94,7 +94,7 @@ To match multiple clients with an exception one can couple `rules.except` or
 
     { rule_any = { class = { "Pidgin", "Xchat" } },
       except_any = { role = { "conversation" } },
-      properties = { tag = tags[1][1] }
+      properties = { tag = "1" }
     }
 
     { rule = {},