Drop the config that 0.16.0 and swift-format already say

[3lvis]

Why

Three .swift-format keys and four .oida.yml entries repeat what the tools already say on their own. maximumBlankLines: 1, respectsExistingLineBreaks: true and lineBreakBeforeEachArgument: false are swift-format's own defaults. unneeded_override, force_cast and force_try became default-on rules in oida 0.16.0, so listing them under opt_in_rules asks for what is already running.

opening_brace's ignore_multiline_function_signatures is the one that changes code. It let a wrapped signature keep its brace on a line of its own; with it gone, the brace joins the closing paren — ) async throws -> HTTPExchange { — which is the shape swift-format emits anyway. Six files picked that up from bin/lint --fix.

Config left: four keys in .swift-format, and one key under opening_brace that stays load-bearing — a multi-line if or guard still wants its brace below the conditions, so the body reads as the body.

The approach

Measured rather than reasoned. Formatting master's whole tree with the six-key config and with the pruned one gives byte-identical output, and the 0.16.0 rule table reports all three opt-ins as opt-in: no, enabled: yes after their removal.

Testing

make test (180 tests, green) plus bin/lint --check clean.

Learnings

Little — the tools' own defaults were the whole answer.