bytes: articulate the doc to show results of Split() given various inputs

[leventov]

It would be nice if bytes.Split() documented whether it returns an empty slice as the first/last slice of subslices if the input starts with the separator sequence or ends with the separator sequence, and also what does bytes.Split() return given an empty input: empty slice or a slice containing a single element - an empty slice.

[odeke-em]

Thank you for this report @leventov!

The doc for strings contains more information and covers all the requests cases except for the one in which the separator is the first or last element https://golang.org/pkg/strings/#Split

Kindly pinging our articulator in chief @robpike.

[cagedmantis]

/cc @bradfitz @ianlancetaylor

[ghost]

its also vague on when an empty slice is returned. strings.Split explains it:

If both s and sep are empty, Split returns an empty slice.

https://godocs.io/strings#Split

bytes.Split has the same behavior, but its not documented:

https://godocs.io/bytes#Split