Complete documentation of SVG renderer

[ganeshgore]

Finish documentation following class and add in documentation tree as well

spydrnet-physical/spydrnet_physical/composers/svg/composer.py

Line 19 in ae5fa8b

# TODO

Here is the example

spydrnet-physical/examples/basic/display_hierarchical_netlist.py

Line 34 in ae5fa8b

composer = SVGComposer()