Fix completion docs URLs

Signed-off-by: Steve Durrheimer <[email protected]>

docs/completion.md

@@ -23,7 +23,7 @@ On a Mac, install with `brew install bash-completion`
 
 Place the completion script in `/etc/bash_completion.d/` (`/usr/local/etc/bash_completion.d/` on a Mac), using e.g.
 
-     curl -L https://raw.githubusercontent.com/docker/compose/$(docker-compose --version | awk '{print $2}')/contrib/completion/bash/docker-compose > /etc/bash_completion.d/docker-compose
+     curl -L https://raw.githubusercontent.com/docker/compose/$(docker-compose --version | awk 'NR==1{print $NF}')/contrib/completion/bash/docker-compose > /etc/bash_completion.d/docker-compose
 
 Completion will be available upon next login.
 
@@ -32,7 +32,7 @@ Completion will be available upon next login.
 Place the completion script in your `/path/to/zsh/completion`, using e.g. `~/.zsh/completion/`
 
     mkdir -p ~/.zsh/completion
-    curl -L https://raw.githubusercontent.com/docker/compose/$(docker-compose --version | awk '{print $2}')/contrib/completion/zsh/_docker-compose > ~/.zsh/completion/_docker-compose
+    curl -L https://raw.githubusercontent.com/docker/compose/$(docker-compose --version | awk 'NR==1{print $NF}')/contrib/completion/zsh/_docker-compose > ~/.zsh/completion/_docker-compose
 
 Include the directory in your `$fpath`, e.g. by adding in `~/.zshrc`
 
@@ -66,4 +66,4 @@ Enjoy working with Compose faster and with less typos!
 - [Get started with Wordpress](wordpress.md)
 - [Command line reference](cli.md)
 - [Yaml file reference](yml.md)
-- [Compose environment variables](env.md)
+- [Compose environment variables](env.md)