Rm unneeded `<a =''>`
Author: mishig25
Pull request: yes

# What does this PR do?

For hashlink generation, `<a id='seq_imdb'></a>` is not used.
Instead, hashlinks are generated from the markdown headings using [these rules](https://github.com/huggingface/doc-builder/blob/21972fd444094cd6c7414968c6a58935047c5dd1/src/doc_builder/build_doc.py#L264-L266)

cc: @stas00 this pr will fix https://huggingface.slack.com/archives/C02GLJ5S0E9/p1644426635823319

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Comments:
_The documentation is not available anymore as the PR was closed or merged._

This will breaking existing links to those anchors (when they don't match the section name just after), which is the reason why they are here.

ooh I see 😊
then I'll push another PR that only fixes dpeespeed.mdx issue mentioned [here](https://huggingface.slack.com/archives/C02GLJ5S0E9/p1644490837265109?thread_ts=1644426635.823319&cid=C02GLJ5S0E9)