Updated the signature for Kernel#Float

[sampersand]

This updates the signature for Kernel#Float.

The way the code checks for Float is pretty interesting:

• If it's an Integer, Float, or Rational, then it's immediately converted to a float and returned.
• If it's a String, then it calls rb_str_to_dbl(), passing along whether an exception should occur
• Otherwise, the .to_f method is called on the argument.

Note that if exception: false is given, the return value may be nil. In addition, when exception: false is supplied, any type can be given for the first argument, but the return value is always nil.

[sampersand]

Consolidated in #1445