Floating point printing should print shortest round-trip value

Description

Currently, Catch2 uses iostream with fixed precision for printing float and double. This is fine, until it's not. Consider comparing two doubles that are 1 ULP apart:

CHECK(5.000000000000001e-05 == 5e-05);

This fails with the amusingly unhelpful:

/app/example.cpp:4: FAILED:
  CHECK( 5.000000000000001e-05 == 5e-05 )
with expansion:
  0.00005 == 0.00005

I have to go through and change Catch::StringMaker<double>::precision to be at least 20 to see the difference, but really also exactly 20 to have sensible output. Here are different precision outputs, compared to the output we get with format (std::format / fmt::format / std::to_chars):

The last line is just a lot better. I don't think there's even a set of options across iostreams/iomanip to give you this output.

Additional context

Out of the box std::to_chars would give this result. I don't know what the compiler requirements are for Catch2 to know whether that's a viable option. Otherwise, there's an increasing number of impressive floating point writing algorithms that you could just consume, e.g. zmij.