Add filtering content (#3355)

* Updated 100-filtering.md added content

* Update content

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Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

src/roadmaps/angular/content/101-rxjs-basics/104-operators/100-filtering.md

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 # Filtering
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+RxJS provides a variety of filtering operators that you can use to filter and transform the data in a stream. You can use these operators in combination with other RxJS operators to create powerful and efficient data processing pipelines.
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+Visit the following resources to learn more:
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+- [Understanding RxJS Operators]( https://rxjs.dev/api/operators)