entry-forms: set type of amount input to text, fix #824 (#827)
entry-forms: set type of amount input to text, fix #824 (#827)

As the amount field is not just for numbers but also the currency, the
"tel" type is not sufficient for that and in particular means on-screen
keyboards will not offer any way to enter the currency.
aumayr/beancount-web,beancount/fava,yagebu/fava,aumayr/beancount-web,yagebu/fava,yagebu/fava,yagebu/fava,beancount/fava,beancount/fava,aumayr/beancount-web,aumayr/beancount-web,beancount/fava,yagebu/fava,beancount/fava