Support for text based stub libraries (.tbd) files

Thank you for maintaining goblin. It is a joy being able to open binary files from any platform and analyze their contents without having to install a myriad of tools to support various binary formats.

I recently found myself wanting to parse text based stub libraries (.tbd files) from Rust and was curious if you would be receptive to including support in goblin. (I _might_ contribute support myself.)

`.tbd` files are essentially descriptors of mach-o dylibs. Apple uses them in their SDKs to describe dylibs. I think the motive behind these files is it enables linkers to do their job using a minimal representation of the dylib without having to ship full dylibs in SDKs. This helps reduce the size of the SDK.

I'm unsure if there is a canonical specification for this file format. However, there's a comprehensive inline comment in the LLVM source code at https://github.com/llvm/llvm-project/blob/main/llvm/lib/TextAPI/MachO/TextStub.cpp that defines it.

The file format is YAML. If I were to implement support for parsing these files in Rust, I'd likely define a bunch of Rust structs representing the various components and then use serde for (de)serialization from/to YAML. If we did this in goblin, we'd pick up a handful of new crate dependencies. I'm unsure if that would be desirable. Of course, we could always define a conditional crate feature to toggle support for text based stub libraries.

Given that text based stub libraries describe mach-o libraries and are used widely on Apple platforms, I can make a compelling case for their inclusion in goblin as a supported format. I was unable to find any Rust crates for parsing this file format on crates.io, so there appears to be a market need.

Are you interested in supported text based stub libraries in goblin? If so, do you have any thoughts on YAML parsing and new crate dependencies?

Start with LLVM's llvm/lib/TextAPI/MachO/TextStub.cpp, which the issue identifies as the format reference, and review goblin's existing Mach-O support and dependency conventions. The issue names no goblin files or tests; done would require agreeing on the parser scope, YAML dependency approach, feature design, and validation coverage.

Written by the indexing model from the issue text.