Make corrections to Finnish locale translations

[lmalmber]

Months and days of the week are written lowercase in Finnish. The list of short days also included a duplicate Sunday in place of Saturday.

Another library I use in the same project with Plotly.js does this correctly, which is why I noticed this:
https://github.com/charliekassel/vuejs-datepicker/blob/master/src/locale/translations/fi.js

Sources:

• Institute for the Languages of Finland: Months, Days
• I am a native speaker of Finnish

[etpinard]

Thanks! Would you be interested in filling up the dictionary translating expression from https://github.com/plotly/plotly.js/blob/master/dist/translation-keys.txt ?

[lmalmber]

Hey, I added the dictionary translations. I don't currently know any other Finnish person I could refer to double check them, but I'm fairly satisfied with the translations.

[etpinard]

Thanks very much! This will be part of 1.43.0.