Update README template

[samreid]

During code review in phetsims/ph-scale#323, I saw this stale-looking documentation:

(3) Transpile the TypeScript code to JavaScript by running grunt output-js-project --live.

[samreid]

I asked on slack:

Can a developer volunteer to review the minor documentation changes in #1623 before I grunt update the README files in all repos?

[samreid]

Contact us at our Google Group

That part should probably be updated...

[samreid]

I forgot this would update overnight, so the changes above are already live across all repos. 😓

[samreid]

@marlitas volunteered to take a look, thanks!

[marlitas]

I don't fully understand why you removed this: (You will probably need to modify this URL based on your HTTP port and relative path.)

Is the port hardcoded into grunt dev-server? Is the relative path not potentially different? I might be missing something that grunt dev-server does automatically for us now. Maybe it would be good to mention that in the README just in case?

[samreid]

Yes, the port is hardcoded (defaults to 80) and I always run it with grunt dev-server from any repo. There is already a link to the developer guide--if we need to put more about the grunt dev-server options, could it be done there?

UPDATE: I'm hoping to frame the README as simpler and less intimidating, for the default case.

[marlitas]

Cool, that sounds good to me. I think we just need to determine if we want to update the google group language? I can ping @brettfiedler