Revive incremental compilation working group

[pnkfelix]

Adapting check-list of things to do from #282

• Create (really, reusing pre-existing) Github label WG-incr-comp
  • Decide on what name to use. (I.e. whether to treat pre-existing WG-compilation-incr WG github label as overriding precedent, or use something else like WG-incr-comp to match up with A-incr-comp...)
    • discussed with @wesleywiser and @spastorino ; we're renaming it to WG-incr-comp!
• Create Zulip stream #t-compiler/wg-incr-comp
• Check if compiler team meeting pages for WG updates need any changes (didn't @spastorino add a magic number on @pnkfelix's suggestion to keep the near-term order stable when new WG's are added?)
• Solicit membership from people who have expressed interest, have relevant expertise, etc. (This check box is "done when its done")
• Write a guide giving some high-level guidelines like add cleanup crew rustc-dev-guide#556
• Create the team toml file in team repo (see PR Create wg-incr-comp team#367)
• Create a sample PR for adding yourself, similar to add nikomatsakis to LLVM ICE-breakers team#140
• Link to the sample PR in this section of the rustc-guide
• Write an announcement blog post

[spastorino]

Check if compiler team meeting pages for WG updates need any changes (didn't @spastorino add a magic number on @pnkfelix's suggestion to keep the near-term order stable when new WG's are added?)

Going to check the box related to this thing. We do have a magic number so we have a way to adjust things.

[spastorino]

Added the sample PR rust-lang/team#371

[spastorino]

@pnkfelix going over this I think

Solicit membership from people who have expressed interest, have relevant expertise, etc. (This check box is "done when its done") is done
Write a guide giving some high-level guidelines like rust-lang/rustc-dev-guide#556 unsure
Link to the sample PR in this section of the rustc-guide unsure about this
Write an announcement blog post I guess this is pending

But besides from that I'm not sure if all that stuff is needed?.