[Documentation] Fix quotes for windows installations

[pcmoritz]

Why are these changes needed?

Escaping on the windows shell with ' doesn't work, we need to use ". Otherwise you get an error like

ERROR: Invalid requirement "'ray[default]'"

or

ERROR: Invalid requirement "'ray[rllib]'"

or

ERROR: Invalid requirement "'ray[tune]'"

or

ERROR: Invalid requirement "'ray[serve]'"

or

ERROR: Invalid requirement "'ray[data]'"

Related issue number

Checks

• 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 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 :(

[richardliaw]

Looks good, will have to have Eric/Chen sign off.

[ericl]

We don't actually need quotes right? It would be better to remove them entirely from the command examples.

[pcmoritz]

There are some shells that need quotes, like zsh which is the standard in macOS:

(base) ➜  ray git:(master) ✗ pip install ray[rllib]
zsh: no matches found: ray[rllib]

I think using " to quote is the safest and works on all platforms (bash on linux, zsh on macOS and cmd on windows).

[scv119]

LGTM