[Doc] Add improved 'ray start --resources' help

[peytondmurray]

Why are these changes needed?

This PR clarifies usage of ray start --resources and gives an example of valid usage on Windows.

Related issue number

Closes #34818.

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[mattip]

Maybe a triple-quoted string could be used to preserve line formatting, and with a touch of dedent to make it pretty? Also, note this is for the windows cmd command prompt. For powershell, additional escaping is needed. Maybe all this should only be added to the help text for windows, to give posix users less of an opportunity to laugh at windows users.

ray start --head --resources="{\""special_hardware\"":1, \""custom_label\"":1}"

[mattip]

LGTM. I confirmed the change only happens on windows. FWIW, the help looks like

 --resources TEXT                A JSON serialized dictionary mapping
                                  resource name to resource quantity.
                                  
                                  Windows command prompt users must ensure to
                                  double quote command line arguments; since
                                  JSON requires the use of double quotes these
                                  must be escaped as well, e.g.
                                  
                                      ray start --head
                                      --resources="{\"special_hardware\":1,
                                      \"custom_label\":1}"
                                  
                                  Windows powershell users need additional
                                  escaping:
                                  
                                      ray start --head
                                      --resources="{\""special_hardware\"":1,
                                      \""custom_label\"":1}"

[angelinalg]

Some style nits.

[peytondmurray]

@jjyao Would you be able to merge this?