docs: fix broken links in README and model references

[godarrenw]

Description

Fixes four broken links: the docs badge and the emoji-key link in the README, and the AAAI reference in the DLinear/NLinear docstrings.

1. Docs badge points at the retired site (README.md:16)

nixtla.github.io/neuralforecast is no longer served and returns 404. This affects the badge twice: the link goes nowhere, and because shields.io probes that same URL for its up/down state, the badge currently renders red. The badge SVG served today reports aria-label="docs: down"; with the URL updated it reports aria-label="docs: up".

README.md:58 already links to nixtlaverse.nixtla.io, so this looks like the one spot the docs migration missed — it is the only remaining nixtla.github.io reference in the repository. The probe protocol is also bumped from http to https to match.

2. AAAI reference points at the wrong article (dlinear.py:88, nlinear.py:52)

Both docstrings cite Zeng et al., Are Transformers Effective for Time Series Forecasting? but link AAAI/article/view/27695, which 404s.

The correct article ID is 26317. Verified via Crossref — DOI 10.1609/aaai.v37i9.26317 resolves to:

• title: Are Transformers Effective for Time Series Forecasting?
• authors: Zeng, Chen, Zhang, Xu
• Proceedings of the AAAI Conference on Artificial Intelligence, 2023, pp. 11121–11128

The volume and issue (v37i9) match the Vol. 37. No. 9. 2023 already written in the citation text, and https://ojs.aaai.org/index.php/AAAI/article/view/26317 returns 200.

3. all-contributors emoji key (README.md:135)

allcontributors.org/docs/en/emoji-key 404s. This uses the current canonical URL https://allcontributors.org/en/reference/emoji-key/ (200) rather than a URL that merely redirects. The line sits outside the ALL-CONTRIBUTORS-LIST markers, so the bot will not overwrite it.

How I checked

Extracted every http(s) URL from the repository's Markdown and Python files and resolved each with curl -L, keeping only genuine 404s — redirects that still resolve were left alone. The AAAI article ID was confirmed against Crossref rather than by guessing an offset. Both badge states were read from the live shields.io SVG.

Documentation only — the two Python changes are inside docstrings, python -m py_compile passes on both, and no functional code is touched.

Disclosure: prepared with AI assistance; every link and the article identity were verified manually.

[CLAassistant]

All committers have signed the CLA.