[DOC] Docstring of 'tol'

[mscheltienne]

Spotted this remaining TODO item:

pycrostates/pycrostates/cluster/kmeans.py

Lines 36 to 46 in c8bcc0a

	tol : float
	Relative tolerance with regards estimate residual noise in the cluster
	centers of two consecutive iterations to declare convergence.
	%(random_state)s
	References
	----------
	.. footbibliography::
	"""
	# TODO: docstring for tol doesn't look english

Maybe:

Convergence criterium: relative tolerance with regard to the estimated 
residual noise in the cluster centers of two consecutive iterations.

cc @vferat