Update population.md / found a repetition (#188)

* Update population.md

Just noticed this repetition, and trying to get used to edit (commit) in GitHub.

* adressed Amit's comment

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Co-authored-by: Amit Moryossef <amitmoryossef@gmail.com>

docs/docs/facts/population.md

@@ -54,7 +54,6 @@ From our research, it is unclear how many people use sign languages.
 [^wfd]: World Federation of the Deaf. 2024. [Our Work](https://wfdeaf.org/our-work/).
 [^un-national-day]: United Nations. 2024. [International Day of Sign Languages](https://www.un.org/en/observances/sign-languages-day).
 
-It is unclear how many people use sign languages.
 The European Centre for Modern Languages[^ecml] estimates that on average,
 deaf sign language users make up about 0.16% of the whole population in any given country, amounting to 12 million people worldwide.
 According to Ethnologue (via Derivation[^derivation]), there are 24 million native sign language users worldwide,