[feat] `Cargo.toml` tab-completion enhancement

[loynoir]

Is your feature request related to a problem? Please describe. Better manage Cargo.toml without human typing, just use tab-completion.

Describe the solution you'd like

[dependencies]
foobar = { version = "<Tab></Tab>" }

Currently, the version tab-completion candidate is

1. ""

2. "*"

Suggest

1. search cargo for foobar versions

2. Use these versions as tab-completion candidate

3. If there are >=30 versions, and if consider harmful for UI performance, only show the latest of each major version.

[dependencies]
foobar = { version = "1.2.3", features = [<Tab></Tab>] }

Currently, the features element tab-completion candidate is

• None

Suggest

1. search cargo for [email protected] features

2. Use these features as tab-completion candidate

Describe alternatives you've considered

Additional context