Updated Spanish translation

[HadrienGardeur]

Based on a review made by Libranda, here's an updated Spanish translation for Thorium.

[danielweck]

Thank you very much, I updated the wiki page https://github.com/edrlab/thorium-reader/wiki/Localization-(l10n)-language-translations
Note that @nvdaes (Noelia) is the original contributor of the Spanish translation. I am merging this Pull Request immediately, but I want to make sure that Noelia is aware of the proposed (and now approved) changes.

[nvdaes]

Hello: Thanks for this update. I see that this fixes some mistakes made by me: autor instead of my mistake author, se instead of Se, and (lectura en voz alta), where I ommited () symbols.
Other messages are similar and maybe a matter of preference. For router instead of rúter, Fundeu prefers to use "rúter":

https://www.fundeu.es/dudas/palabra-clave/ruter/

Anyway, router is also acceptable.
Kind regards.