Rollup merge of rust-lang#39777 - mina86:gib, r=steveklabnik

book: binary prefixed are defined by IEC and not in SI

Binary prefixes (such as Gi for ‘gibi-’ in GiB) are defined by
International Electrotechnical Commission (IEC) and not in the
International System of Units (SI).

Though to be honest I’d just reword the previous paragraph to use ‘1 GiB’.

Author: frewsxcv

src/doc/book/src/the-stack-and-the-heap.md

@@ -86,7 +86,7 @@ to a large number, representing how much RAM your computer has. For example, if
 you have a gigabyte of RAM, your addresses go from `0` to `1,073,741,823`. That
 number comes from 2<sup>30</sup>, the number of bytes in a gigabyte. [^gigabyte]
 
-[^gigabyte]: ‘Gigabyte’ can mean two things: 10^9, or 2^30. The SI standard resolved this by stating that ‘gigabyte’ is 10^9, and ‘gibibyte’ is 2^30. However, very few people use this terminology, and rely on context to differentiate. We follow in that tradition here.
+[^gigabyte]: ‘Gigabyte’ can mean two things: 10<sup>9</sup>, or 2<sup>30</sup>. The IEC standard resolved this by stating that ‘gigabyte’ is 10<sup>9</sup>, and ‘gibibyte’ is 2<sup>30</sup>. However, very few people use this terminology, and rely on context to differentiate. We follow in that tradition here.
 
 This memory is kind of like a giant array: addresses start at zero and go
 up to the final number. So here’s a diagram of our first stack frame: