Update Spanish translation of basics.md

[gclaramunt]

Spanish translation of Basic scala

[gclaramunt]

Some details are missing (intro and fiddle run), I'll add them asap

[NthPortal]

Thanks for doing this! I can't review it as I am not fluent, but it's definitely something we need more of ❤️

[gclaramunt]

Who can review? I can ask someone who speak Spanish :)

[dwijnand]

Perhaps @diesalbla, @jvican, and/or @ignasi35 have some spare bandwidth?

[diesalbla]

A few comments.
General changes:

• Replace "palabra clave" (too direct translation of keyword) by "palabra reservada".
• Use the singular form, in preference to the plural form.

[gclaramunt]

Thanks for the review :)

[ignasi35]

This looks great! I've left a couple of major comments and a handful of small typo fixes.

[gclaramunt]

Ya le pase el corrector y en contre un par de tildes mas que faltaban.

[SethTisue]

thanks all!