Allow ignoring function signatures (or setting a different max length) to align with standard library idioms

[danrneal]

Welcome

• Yes, I've searched similar ideas on GitHub and didn't find any.
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How did you install golines?

Official binary

Your feature request related to a problem? Please describe

Currently, golines applies --max-len uniformly across all AST nodes. When setting a reasonable limit (e.g., -m 120) to keep business logic and comments readable, it forces function signatures with 4-5 parameters to wrap across multiple lines.

The Go standard library frequently keeps function signatures on a single line even when they exceed typical column limits (e.g., image/draw has signatures over 140 characters). The current golines behavior forces a choice: either accept multiline signatures that diverge from standard library style, or increase --max-len globally and lose formatting strictness for the rest of the file.

Describe the solution you'd like

I would like an option to prevent golines from wrapping function signatures, or to allow them a separate, longer length limit.

Potential solutions:

1. A boolean flag (e.g., --ignore-func-signatures) that skips formatting for func declaration nodes.
2. A separate length configuration (e.g., --max-sig-len=150) that applies a different boundary specifically to function signatures.

Describe alternatives you've considered

1. //golines:ignore: Manually adding this comment above every long signature works, but adds noise and requires manual upkeep.
2. Parameter Objects: Grouping parameters into a dedicated struct just to reduce the signature length. This introduces unnecessary indirection and creates types whose only purpose is to satisfy the formatter.
3. Accepting Multiline Signatures: Letting golines format them across multiple lines. This is my current workaround, but I would prefer the option to maintain single-line signatures.

Additional context

No response