Improve documentation of mesh2d_delete_small_flow_edges_and_small_triangles

[veenstrajelmer]

What is the need for this task.
The function mesh2d_delete_small_flow_edges_and_small_triangles raises several questions.

What is the task?
There was an explanation given in Deltares/dfm_tools#812 (comment) about mesh2d_delete_small_flow_edges_and_small_triangles. This function is also documented, but this is a bit less clear than in the issue comment. I suggest to slightly clarify this:

MeshKernelPy/meshkernel/meshkernel.py

Lines 997 to 1004 in ceba150

	"""Deletes all small mesh2d flow edges and small triangles.
	The flow edges are the edges connecting faces circumcenters.
	Args:
	small_flow_edges_length_threshold (float): The configurable length for detecting a small flow edge.
	min_fractional_area_triangles (float): The ratio of the face area to the average area of neighboring
	non-triangular faces. This parameter is used for determining whether
	a triangular face is small.

It would also be good if sensible argument default vlaues are set or mentioned in the docstring.