documentation introduction added.
Introduced one exception to the rule that we usually don't have float64 literals: At the beginning of an expression (or a variable name) we're allowing a float64 literal. Since we know we started the parsing with an integer which can't obviously be a variable name, we can check whether the first number is followed by dot (and then a number again). If so we're converting it to a float64. This is how Django behaves as well.
floatformat-filter added.