docs(cli): Fix bash completion and link to click's shell completion

Author: tony

docs/cli.md

@@ -8,11 +8,15 @@
 
 ## Completion
 
+```{note}
+See the [click library's documentation on shell completion](https://click.palletsprojects.com/en/8.0.x/shell-completion/) for the most up to date way of connecting completion for vcspull.
+```
+
 In bash (`~/.bashrc`):
 
 ```{code-block} sh
 
-eval "$(_TMUXP_COMPLETE=source tmuxp)"
+eval "$(_TMUXP_COMPLETE=bash_source tmuxp)"
 
 ```