test: precedence of flag vs toml for abci client type

[JimLarson]

Description

Refs: Agoric/agoric-sdk#9224

Add unit tests to confirm order of precedence for flag and TOML settings for ABCI client type. The previous test in start_test.go confirms that the setting is interpreted as desired.

Also more documentation for TOML template. (Flag help strings are more terse and needn't be as wordy.)

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Author Checklist

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I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
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Reviewers Checklist

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I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[JimLarson]

Failing lint check expected, since upstream also fails this check.

[gibson042]

Nice catches here.

[gibson042]

Ugh, the buggy manual synchronization in this file is painful. I'm torn on whether or not we want to fix "ABCIClientType selects the type of ABCI client" to "abci-client-type selects the type of ABCI client" for correctness or leave it alone for local consistency, but am inclined towards the latter. The whole thing is crying out for a reflective approach à la https://go.dev/play/p/W74nda-DQKZ .

No changes needed here, though.

[gibson042]

cosmos#20097 (comment)

Yes 100% agree, we are going to use struct annotations and github.com/pelletier/go-toml/v2 library for server/v2:
https://github.com/cosmos/cosmos-sdk/blob/605b724/server/v2/api/grpc/config.go#L19-L34

🎉