[translations] Translation of pics in text-input

[Till Paala <till.rettig@xxxxxx>]

 Hi Francisco,

I saw you are the only one who has done translation of the originally 
svg-pics of the short introduction into how lilypond works (in the file 
text-input.es.html). How did you do this (it used to be fetched from the 
LANG.po file and applied to the svg-file as a string)?

Greetings
Till