[DOC] Correct documentation for N-BEATS

[Pinaka07]

Reference Issues/PRs

fixes #1881

What does this implement/fix? Explain your changes.

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Did you add any tests for the change?

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PR checklist

• The PR title starts with either [ENH], [MNT], [DOC], or [BUG]. [BUG] - bugfix, [MNT] - CI, test framework, [ENH] - adding or improving code, [DOC] - writing or improving documentation or docstrings.
• Added/modified tests
• Used pre-commit hooks when committing to ensure that code is compliant with hooks. Install hooks with pre-commit install.
  To run hooks independent of commit, execute pre-commit run --all-files

[Pinaka07]

"If the time series denote different entities or exhibit very similar patterns accross the board, a model such as N-BEATS will not work as well."

This might be slightly misleading — N-BEATS is actually designed to work well when time series are from different entities but share similar patterns, as it learns global structures across series.

It typically struggles when the time series are from different entities and exhibit highly diverse or uncorrelated patterns.

Consider rephrasing to:
"If the timeseries denote different entities or exhibit very similar patterns across the board, a model such as N-Beats will not work as well."

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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  Coverage        ?   86.33%           
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  Files           ?       96           
  Lines           ?     7802           
  Branches        ?        0           
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  Hits            ?     6736           
  Misses          ?     1066           
  Partials        ?        0           

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pytest	86.33% <ø> (?)

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[fnhirwa]

Looks Good to me😊

[Pinaka07]

Thanks @fnhirwa 😊