title: How to compare floating point in catch2
body: <p>I am using Catch v2.13.1</p>
  <p>What is the correct way to compare float values. I thought the below would fail, but both pass.</p>
  <pre class="lang-cpp prettyprint-override"><code>REQUIRE(1147332687.7189338 == Approx(1147332688.4281545).margin(0.0001));
  REQUIRE(1147332687.7189338 == Approx(1147332688.4281545));
  </code></pre>
  <p>However this fails as expected</p>
  <pre class="lang-cpp prettyprint-override"><code>REQUIRE(abs(1147332687.7189338 - 1147332688.4281545) &lt;= Approx(0).margin(0.0001));
  </code></pre>
  <p>I don't understand why the first two statements wouldn't work</p>