Change kitty +kitten -> kitten in docs

All kittens except for the broadcast and panel kittens have now been
ported to Go and so can be run with just kitten rather than kitty
+kitten. So update the docs to use this canonical form for launching
kittens

kittens/clipboard/main.py

@@ -60,22 +60,22 @@ the clipboard. Some examples:
 .. code:: sh
 
     # Copy an image to the clipboard:
-    kitty +kitten clipboard picture.png
+    kitten clipboard picture.png
 
     # Copy an image and some text to the clipboard:
-    kitty +kitten clipboard picture.jpg text.txt
+    kitten clipboard picture.jpg text.txt
 
     # Copy text from STDIN and an image to the clipboard:
-    echo hello | kitty +kitten clipboard picture.png /dev/stdin
+    echo hello | kitten clipboard picture.png /dev/stdin
 
     # Copy any raster image available on the clipboard to a PNG file:
-    kitty +kitten clipboard -g picture.png
+    kitten clipboard -g picture.png
 
     # Copy an image to a file and text to STDOUT:
-    kitty +kitten clipboard -g picture.png /dev/stdout
+    kitten clipboard -g picture.png /dev/stdout
 
     # List the formats available on the system clipboard
-    kitty +kitten clipboard -g -m . /dev/stdout
+    kitten clipboard -g -m . /dev/stdout
 '''
 
 usage = '[files to copy to/from]'

kittens/hints/main.py

@@ -134,7 +134,7 @@ window, :code:`window` a new kitty window, :code:`tab` a new tab,
 :code:`os_window` a new OS window and :code:`background` run in the background.
 The actual action is whatever arguments are provided to the kitten, for
 example:
-:code:`kitty +kitten hints --type=linenum --linenum-action=tab vim +{line} {path}`
+:code:`kitten hints --type=linenum --linenum-action=tab vim +{line} {path}`
 will open the matched path at the matched line number in vim in
 a new kitty tab. Note that in order to use :option:`--program` to copy or paste
 the provided arguments, you need to use the special value :code:`self`.

kittens/icat/main.py

@@ -75,7 +75,7 @@ detecting image display support.
 --print-window-size
 type=bool-set
 Print out the window size as <:italic:`width`>x<:italic:`height`> (in pixels) and quit. This is a
-convenience method to query the window size if using :code:`kitty +kitten icat`
+convenience method to query the window size if using :code:`kitten icat`
 from a scripting language that cannot make termios calls.