[equalizing_difference] Editorial notes and suggestions

[HumphreyYang]

Comments by @SylviaZhaooo

Content

• college, high-school -> college-high-school
• ".2" -> "0.2"
• Migrate (Entrepreneur-worker interpretation)[https://intro.quantecon.org/equalizing_difference.html#entrepreneur-worker-interpretation]

Code

• \gamma_h_c -> \gamma_c
• Clean up numpy code
• Clean up the sympy code @HumphreyYang

[HumphreyYang]

Hi @SylviaZhaooo,

The sympy code can be found here: https://github.com/QuantEcon/lecture-python-intro/blob/update-sympy-edm/lectures/equalizing_difference.md

Please feel free to pick from it to form an exercise.

[mmcky]

thanks @HumphreyYang + @SylviaZhaooo is once #522 is merged can we close this issue?