Add guides for zbench to zig-autodoc

[hendriknielaender]

Currently, the documentation generated by zig build docs for the zBench project lacks guides. These guides are essential for users to understand the library beyond the auto-generated API references. They provide context, examples, and deeper explanations of the library's use and capabilities.

Detailed Description

The autogenerated API section is helpful for users already familiar with zBench, but for new users or those looking to understand advanced usage patterns, guides are indispensable. The absence of these guides represents a significant gap in our documentation.

Proposed Solution

We need to create and integrate handwritten guides into our zig-autodoc output. This can be done by specifying markdown files to include in the top-level doc comment of our root file (zbench.zig). Here's an example of how to reference these guides:

//!zig-autodoc-guide: intro.md
//!zig-autodoc-guide: quickstart.md
//!zig-autodoc-guide: advanced-docs/advanced-stuff.md

Action Items

1. Write comprehensive guides covering the following topics:

• Introduction to zBench
• Quickstart guide with basic usage examples
• Technical documentation for in-depth understanding
• Guides for advanced usage patterns

1. Place these guides in the appropriate directory structure (e.g., a docs/ folder at the root of the project).
2. Reference these guides in zbench.zig as shown above.
3. Generate the documentation using zig build docs to verify the inclusion of the guides.

[hendriknielaender]

added basic intro and usage guides, but adv. guides are missing. Created a follow-up issue #28