updated README.rst for 18b directory
updated README.rst for 18b directory

oxfordyang2016/learnfluentpython,fluentpython/example-code,everaldo/example-code,everaldo/example-code,oxfordyang2016/learnfluentpython,Wallace-dyfq/example-code,dcbdmb/example-code,dcbdmb/example-code,Wallace-dyfq/example-code,dcbdmb/example-code,everaldo/example-code,oxfordyang2016/learnfluentpython,oxfordyang2016/learnfluentpython,friebsch/example-code,fluentpython/example-code,everaldo/example-code,friebsch/example-code,dcbdmb/example-code,fluentpython/example-code,friebsch/example-code,dcbdmb/example-code,fluentpython/example-code,friebsch/example-code,oxfordyang2016/learnfluentpython,friebsch/example-code,Wallace-dyfq/example-code,Wallace-dyfq/example-code,everaldo/example-code,Wallace-dyfq/example-code,fluentpython/example-code