Update documentation occurrences of filename .sh

Documentation in the completion scripts for Bash and Zsh state the wrong filenames.

Signed-off-by: Peter van der Does <peter@avirtualhome.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -17,9 +17,9 @@
 #
 # To use these routines:
 #
-#    1) Copy this file to somewhere (e.g. ~/.git-completion.sh).
+#    1) Copy this file to somewhere (e.g. ~/.git-completion.bash).
 #    2) Add the following line to your .bashrc/.zshrc:
-#        source ~/.git-completion.sh
+#        source ~/.git-completion.bash
 #    3) Consider changing your PS1 to also show the current branch,
 #       see git-prompt.sh for details.
 

contrib/completion/git-completion.zsh

@@ -8,7 +8,7 @@
 # If your script is on ~/.git-completion.sh instead, you can configure it on
 # your ~/.zshrc:
 #
-#  zstyle ':completion:*:*:git:*' script ~/.git-completion.sh
+#  zstyle ':completion:*:*:git:*' script ~/.git-completion.zsh
 #
 # The recommended way to install this script is to copy to
 # '~/.zsh/completion/_git', and then add the following to your ~/.zshrc file: