docs: Fix duplicate Known Limitations header

[edgarrmondragon]

$ grep -nri "known limitations" docs
docs/stream_maps.md:359:## Known Limitations
docs/batch.md:97:## Known Limitations

Read the Docs builds are failing because of this

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📚 Documentation preview 📚: https://meltano-sdk--1133.org.readthedocs.build/en/1133/

[codecov]

Codecov Report

Merging #1133 (e9ca016) into main (4b37cad) will not change coverage.
The diff coverage is n/a.

❗ Current head e9ca016 differs from pull request most recent head e93fa4c. Consider uploading reports for the commit e93fa4c to get more accurate results

@@           Coverage Diff           @@
##             main    #1133   +/-   ##
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  Coverage   83.47%   83.47%           
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  Files          42       42           
  Lines        3855     3855           
  Branches      658      658           
=======================================
  Hits         3218     3218           
  Misses        472      472           
  Partials      165      165           

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[WillDaSilva]

Looks good to me. I didn't find anything referencing here the old tag, so this shouldn't break any links within the SDK docs.