Rollup merge of rust-lang#102131 - orlp:patch-1, r=thomcc

Added which number is computed in compute_float.

The original comment was very elaborate but ultimately did not mention at all what is being computed using parameters `w, q`, only referencing an external article for the algorithm.

Author: Dylan-DPC

library/core/src/num/dec2flt/lemire.rs

@@ -6,7 +6,7 @@ use crate::num::dec2flt::table::{
     LARGEST_POWER_OF_FIVE, POWER_OF_FIVE_128, SMALLEST_POWER_OF_FIVE,
 };
 
-/// Compute a float using an extended-precision representation.
+/// Compute w * 10^q using an extended-precision float representation.
 ///
 /// Fast conversion of a the significant digits and decimal exponent
 /// a float to an extended representation with a binary float. This