split using isspace

[simonbyrne]

Similar to #27232, this tweaks split to use isspace instead of just unicode delimiters.

[fredrikekre]

Can we change the argument order in a non-breaking way? split(isspace, str) seems more natural.

[simonbyrne]

Not in this case, since split(::String, ::String) is valid.

[simonbyrne]

If we merge both PRs, then _default_delims will only then be used in

julia/base/shell.jl

Lines 7 to 16 in 779cf84

	# strips the end but respects the space when the string ends with "\\ "
	function rstrip_shell(s::AbstractString)
	c_old = nothing
	for (i, c) in Iterators.reverse(pairs(s))
	((c == '\\') && c_old == ' ') && return SubString(s, 1, i+1)
	c in _default_delims || return SubString(s, 1, i)
	c_old = c
	end
	SubString(s, 1, 0)
	end

[simonbyrne]

Changing the ordering would match findXX methods, but would be different from join.

[ViralBShah]

Rebased on master.

[nalimilan]

"occurrences". Could also say "delimiter(s)".