minor #18266 Fix missing link (mikaelkael)

This PR was submitted for the 6.3 branch but it was merged into the 5.4 branch instead.

Discussion
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Fix missing link

Compilation broken by ac6b7f7

Commits
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39bca2d Fix missing link

Author: javiereguiluz

frontend/_ux-libraries.rst.inc

@@ -38,6 +38,7 @@
 .. _`Chart.js`: https://www.chartjs.org/
 .. _`Swup`: https://swup.js.org/
 .. _`React`: https://reactjs.org/
+.. _`Svelte`: https://svelte.dev/
 .. _`Turbo Drive`: https://turbo.hotwired.dev/
 .. _`Typed`: https://github.com/mattboldt/typed.js/
 .. _`Vue`: https://vuejs.org/