Auto merge of #3618 - sbeckeriv:3473-new-subcommand-doc-update, r=alexcrichton

Update new command help doc

Resolves #3473

Dearest reviewer,

I hope that all is well in rustland. I was reviewing some open issues
and saw this update to the help text for the new command. I have added
the suggested help text from issue #3473. I formated to the message to
match the publish bin's job flag.

Thank you for your time,
Becker

src/bin/new.rs

@@ -31,7 +31,7 @@ Options:
                         control at all (none) overriding a global configuration.
     --bin               Use a binary (application) template
     --lib               Use a library template
-    --name NAME         Set the resulting package name
+    --name NAME         Set the resulting package name, defaults to the value of <path>
     -v, --verbose ...   Use verbose output (-vv very verbose/build.rs output)
     -q, --quiet         No output printed to stdout
     --color WHEN        Coloring: auto, always, never