doc: landing page code cleanup

[Becheler]

Before submitting

• This PR targets the develop branch.
• I searched for an existing PR or issue covering the same change.
• My contribution is licensed under the Boost Software License 1.0.

Type of change

• Bug fix
• New feature or API addition
• Refactor (no behavior change)
• Documentation
• Build, CI, or tooling
• Other (specify below)

Does this PR introduce a breaking change?

• Yes (describe migration impact below)
• No

What this PR does

1. Increase length of video
2. Make the link explicit between the video and the example
3. Clean up the example code as recommended by Andrzej
4. Add an Author and How to Cite section

Motivation

See recent Boost Mailing List poll.

Testing

Checklist

• Existing tests pass (b2 in the test/ directory).
• New behavior is covered by a test, or this is a docs / build / refactor change.
• Documentation was updated if user-facing behavior changed.
• No new compiler warnings on the platforms I built against.

[cppalliance-bot]

An automated preview of the documentation is available at https://509.graph.prtest3.cppalliance.org/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-06-22 08:30:25 UTC

[github-actions]

Compiler-warning counts vs develop (auto-generated).
PR run 27939739631 vs develop run 27866501982 (32fe89d9ca).

Job	Baseline	After	Delta
macos (clang, 14)	46	46	0
macos (clang, 17)	41	41	0
macos (clang, 20)	41	41	0
ubuntu (clang-19, 14)	46	46	0
ubuntu (clang-19, 17)	46	46	0
ubuntu (clang-19, 20)	46	46	0
ubuntu (clang-19, 23)	46	46	0
ubuntu (gcc-14, 14)	28	28	0
ubuntu (gcc-14, 17)	28	28	0
ubuntu (gcc-14, 20)	28	28	0
ubuntu (gcc-14, 23)	28	28	0
windows_msvc_14_3 (msvc-14.3)	974	974	0

[jeremy-murphy]

PR titles, as with git commit messages, should say explain what and why. The backstory (feedback from person X) belongs in the details.

[jeremy-murphy]

It's fine, apart from the awkward choice of variable name that I highlighted.
I'm not sure why the particular code changes are important, though?

[jeremy-murphy]

num_vertices is the same name as the function in Boost.Graph, so creating a variable with that name can be awkward for ADL. If the variable only gets used once, I would consider leaving it out altogether.

Suggested change

	constexpr int num_vertices = 20;
	Graph g(edges.begin(), edges.end(), num_vertices);
	Graph g(edges.begin(), edges.end(), 20);

[Becheler]

I will rename it nb_vertices then. We can't leave it out, as Andrzej and others regularly get confused about what this number in the parameters list is: so it's either a named variable or another comment. I prefer actual code over comments :)