Support "%x" etc. formats on more floats

Support "%x" etc. formats on more floats

* doc/lispref/strings.texi (Formatting Strings): Document this.
* src/editfns.c (styled_format): Support %o, %x, and %X on
finite floats less than zero or greater than UINTMAX_MAX.
* test/src/editfns-tests.el (format-%x-large-float)
(read-large-integer, format-%o-negative-float):
Adjust tests to match extended behavior.
Rename the latter test from format-%o-invalid-float,
since the float is no longer invalid.

* test/src/editfns-tests.el (format-%x-large-float)
(read-large-integer): Test this.