help: Update completions help to include mkdirs

In order to ensure that people have the completions directory
in existence before trying to write to it, include `mkdir -p`
commands in the completions help.

Signed-off-by: Daniel Silverstone <[email protected]>

Author: kinnison

src/cli/help.rs

@@ -169,6 +169,7 @@ r"DISCUSSION:
     `~/.local/share/bash_completion/completions` for user-specific commands.
     Run the command:
 
+        $ mkdir -p ~/.local/share/bash_completion/completions
         $ rustup completions bash >> ~/.local/share/bash_completion/completions/rustup
 
     This installs the completion script. You may have to log out and
@@ -179,13 +180,15 @@ r"DISCUSSION:
     Homebrew stores bash completion files within the Homebrew directory.
     With the `bash-completion` brew formula installed, run the command:
 
+        $ mkdir -p $(brew --prefix)/etc/bash_completion.d
         $ rustup completions bash > $(brew --prefix)/etc/bash_completion.d/rustup.bash-completion
 
     FISH:
 
     Fish completion files are commonly stored in
     `$HOME/.config/fish/completions`. Run the command:
 
+        $ mkdir -p ~/.config/fish/completions
         $ rustup completions fish > ~/.config/fish/completions/rustup.fish
 
     This installs the completion script. You may have to log out and