math/big: fix typo of comment (`BytesScanner` to `ByteScanner`)
math/big: fix typo of comment (`BytesScanner` to `ByteScanner`)

Change-Id: I0c2d26d6ede1452008992efbea7392162da65014
Reviewed-on: https://go-review.googlesource.com/c/go/+/331651
Reviewed-by: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,cloudflare/go,golang/go,nawawi/go,nawawi/go,nawawi/go,cloudflare/go,nawawi/go,CAFxX/go,CAFxX/go,golang/go,golang/go,CAFxX/go,CAFxX/go,cloudflare/go,golang/go,cloudflare/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,cloudflare/go,golang/go,nawawi/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,cloudflare/go,CAFxX/go,CAFxX/go