Drop a pedantry-triggering sentence about IEEE-754

The pedantry is accurate, but since we can just drop this entirely, it
will cut the potential distraction for readers who might get hung up on
it otherwise!

Fixes #3818

src/ch03-02-data-types.md

@@ -141,8 +141,7 @@ Here’s an example that shows floating-point numbers in action:
 {{#rustdoc_include ../listings/ch03-common-programming-concepts/no-listing-06-floating-point/src/main.rs}}
 ```
 
-Floating-point numbers are represented according to the IEEE-754 standard. The
-`f32` type is a single-precision float, and `f64` has double precision.
+Floating-point numbers are represented according to the IEEE-754 standard.
 
 #### Numeric Operations