Contributor's Guide Further Update

[daijingz]

Previously there was an issue with inserting commit message guidance into the contributor's guide. This inspires me, as there is a possible improvement in the contributor's guide:

In the first situation, the definition has left different amounts' spacings in order to bring the same indentation level to the operator =, while the second situation only allows one space between different things. These are two different indentations.

In the previous issues, I did not know which case we should use the first situation, and which case we should use the second situation. I did not find useful information in the contributor's guide.

@JacquesCarette, I feel some requirements become invisible or ambiguous. Sometimes I do not know some requirements, and sometimes there are collisions between different requirements. (Similar as conflicts)

There is something I want to improve:

1. Insert an information field inside "Coding Style", to include information about definition spacing. (There are many different cases for spacing, each case should be summarized into requirements, and should include a good example inside for each case)

MORE Points are coming.