fix(forge doc): use relative path instead of full path

[marcvernet31]

Motivation

Fix issue described here: #12361

Solution

Fix forge doc hyperlinks to use relative paths

• Generate relative links like /src/... instead of absolute filesystem paths
• Ensure consistent path handling across builder, document, inheritance, and writer

Added a test on doc.rs to ensure paths are no longer relative.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[grandizzy]

I think we still need this, as docs target paths are composed prefixed with SRC here:

foundry/crates/doc/src/builder.rs

Line 194 in 87a024e

let target_path = out_dir.join(Self::SRC).join(relative_path);

foundry/crates/doc/src/builder.rs

Line 219 in 87a024e

let target_path = out_dir.join(Self::SRC).join(relative_path);

foundry/crates/doc/src/builder.rs

Line 247 in 87a024e

let target_path = out_dir.join(Self::SRC).join(relative_path);

so it's a doubled src e.g. target path is /home/flow/docs/src/src/interfaces/IFlowNFTDescriptor.sol/interface.IFlowNFTDescriptor.md and out target is /home/flow/docs hence relative path will result in doubled src. Or we could just not join src in target dirs, maybe that's better

[marcvernet31]

Added strip_prefixback there.

[grandizzy]

thank you!