Misleading doc for insert!(sc, k)

[SimonCoste]

The following method call should be insert!(sc, k, v) and not insert!(sc, k).

DataStructures.jl/src/sorted_multi_dict.jl

Lines 152 to 166 in 4cc80fb

	"""
	insert!(sc, k)
	Argument `sc` is a SortedDict or SortedMultiDict, `k` is a key and
	`v` is the corresponding value. This inserts the `(k,v)` pair into
	the container. If the key is already present in a SortedDict, this
	overwrites the old value. In the case of SortedMultiDict, no
	overwriting takes place (since SortedMultiDict allows the same key
	to associate with multiple values). In the case of SortedDict, the
	return value is a pair whose first entry is boolean and indicates
	whether the insertion was new (i.e., the key was not previously
	present) and the second entry is the semitoken of the new entry. In
	the case of SortedMultiDict, a semitoken is returned (but no
	boolean). Time: O(*c* log *n*)
	"""

Also, this doc entry should be merged with this duplicate:

DataStructures.jl/src/sorted_dict.jl

Lines 256 to 270 in 4cc80fb

	"""
	insert!(sc, k)
	Argument `sc` is a SortedDict or SortedMultiDict, `k` is a key and
	`v` is the corresponding value. This inserts the `(k,v)` pair into
	the container. If the key is already present in a SortedDict, this
	overwrites the old value. In the case of SortedMultiDict, no
	overwriting takes place (since SortedMultiDict allows the same key
	to associate with multiple values). In the case of SortedDict, the
	return value is a pair whose first entry is boolean and indicates
	whether the insertion was new (i.e., the key was not previously
	present) and the second entry is the semitoken of the new entry. In
	the case of SortedMultiDict, a semitoken is returned (but no
	boolean). Time: O(*c* log *n*)
	"""

Another duplicate was pointed in #559 for pop!(sc, k).

[StephenVavasis]

Closed via #787