Auto-complete oddities when filtering fields

Description

Under some circumstances, attempting to use the auto-completion on vector fields (as in adding lines for plots or trying to show a particular field in the Raw Messages panel) works poorly.

The below is all based on the state of studio.foxglove.dev as of 2022.05.26 (1.12.1-dev), using log.mcap.gz

Steps To Reproduce

These are two separate issues (not ordered steps):

1. Fill in "/localizer frc971.IMUValuesBatch".readings[:] – no auto-complete suggestions will be forthcoming
2. Start typing imuvalues. The autocomplete suggests will include "/localizer frc971.IMUValuesBatch".readings.accelerometer_x. (which is incorrect in two ways–(1) that readings is a vector and (2) that accelerometer_x is a scalar field and so the trailing . is misleading).

Expected Behavior

1. Once you fill in [:] autocompletion should still work.
2. Autocompletion options should always be valid.

Actual Behavior

[foxymiles]

Yeah making your id an int will at least give you some suggestions. It looks like offering suggestions following a user-entered [:] is going to require reworking the autocomplete logic a bit given our current grammar.

[defunctzombie]

The oddities described here have been fixed in #3500 so I’m closing this bug.

We provide no completion for slices currently so that part would be a feature request.