Adds missing html_meta tags

[Sohlar]

Describe your changes

Added raw/meta directives for html_meta tags | SEO improvement

Issue ticket number and link

Closes #290

Checklist before requesting a review

• [ ] I have performed a self-review of my code
• [ ] I have added thorough tests (when necessary).
• [ ] I have added the right documentation in the docstring and changelog (when needed)

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:books: Documentation preview :books:: https://sklearn-evaluation--321.org.readthedocs.build/en/321/

[idomic]

@Sohlar it seems you've just used a placeholder in all of those files? The content needs to be correct: This isn't valid:

<meta name="description" lang="en" content="Some description">
    <meta property="og:locale" content="en_US">

.. meta::
   :keywords: Tag1, Tag2

It should be something descriptive of the page with the right keyword tags.

[coveralls]

Pull Request Test Coverage Report for Build 4461796981

Warning: This coverage report may be inaccurate.

We've detected an issue with your CI configuration that might affect the accuracy of this pull request's coverage report. To ensure accuracy in future PRs, please see these guidelines. A quick fix for this PR: rebase it; your next report should be accurate.

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.404%

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Totals
Change from base Build 4368081770:	0.0%
Covered Lines:	3661
Relevant Lines:	3878

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💛 - Coveralls

[neelasha23]

@Sohlar Are you creating a fresh PR?

[Sohlar]

@neelasha23 Yes, I managed my branches incorrectly and had to delete it. I posted a new example for discussion here https://github.com/ploomber/sklearn-evaluation/issues/290#issuecomment-1476059201