Introduce InlineCompletionProvider

[as-cii]

This pull request introduces a new InlineCompletionProvider trait, which enables making Editor copilot-agnostic and lets us push all the copilot functionality into the copilot_ui module. Long-term, I would like to merge copilot and copilot_ui, but right now project depends on copilot, which makes this impossible.

The reason for adding this new trait is so that we can experiment with other inline completion providers and swap them at runtime using config settings.

Please, note also that we renamed some of the existing copilot actions to be more agnostic (see release notes below). We still kept the old actions bound for backwards-compatibility, but we should probably remove them at some later version.

Also, as a drive-by, we added new methods to the Global trait that let you read or mutate a global directly, e.g.:

MyGlobal::update(cx, |global, cx| {
});

Release Notes:

• Renamed the copilot::Suggest action to editor::ShowInlineCompletion
• Renamed the copilot::NextSuggestion action to editor::NextInlineCompletion
• Renamed the copilot::PreviousSuggestion action to editor::PreviousInlineCompletion
• Renamed the editor::AcceptPartialCopilotSuggestion action to editor::AcceptPartialInlineCompletion

[maxbrunsfeld]

/cc @pjlast @beyang - this might be relevant to your Cody branch.

[rgbkrk]

This branch is failing for two keymap tests, where it tests modifying the base and retaining the users keympa

cargo test --bin Zed keymap
    Finished test [unoptimized + debuginfo] target(s) in 0.48s
     Running unittests src/main.rs (target/debug/deps/Zed-a25a0cca1ed3c648)

running 2 tests
test zed::tests::test_base_keymap ... FAILED
test zed::tests::test_disabled_keymap_binding ... FAILED

failures:

---- zed::tests::test_base_keymap stdout ----
thread 'zed::tests::test_base_keymap' panicked at crates/zed/src/zed.rs:2873:9:
On 2877 Failed to find pane::ActivatePrevItem with key binding [

---- zed::tests::test_disabled_keymap_binding stdout ----
thread 'zed::tests::test_disabled_keymap_binding' panicked at crates/zed/src/zed.rs:3007:9:
On 3011 Failed to find pane::ActivatePrevItem with key binding [
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    zed::tests::test_base_keymap
    zed::tests::test_disabled_keymap_binding

test result: FAILED. 0 passed; 2 failed; 0 ignored; 0 measured; 17 filtered out; finished in 0.59s

error: test failed, to rerun pass `--bin Zed`

The assertion that's failing in both of these tests (near the end of each test):

        // Test modifying the base, while retaining the users keymap
        app_state
            .fs
            .save(
                "/settings.json".as_ref(),
                &r#"
                {
                    "base_keymap": "JetBrains"
                }
                "#
                .into(),
                Default::default(),
            )
            .await
            .unwrap();

        cx.background_executor.run_until_parked();

        assert_key_bindings_for(
            workspace.into(),
            cx,
            vec![("cmd-shift-[", &ActivatePrevItem)],
            line!(),
        )

I couldn't figure out how the changes here might have caused this. After looking into it with @mikayla-maki, we did not find the root cause but maybe found something odd. In handle_keymap_file_changes, we do an unbounded send on base_keymap_tx that never seems to get polled in the base_keymap_rx.next in the select_biased! below it.