Add an option to disable fetch_31() during init Stock

[ianlini]

1. It's a bad idea to send requests in __init__()
2. fetch_31() is a strange method and it sends too many requests (3 in the worst case)
3. In most cases, I want to get the data in a specific month or date, so I don't need the initial fetch_31() and want to fully control what requests I will send

Therefore, I add an option to disable the initial fetch_31(), and leave the default behavior the same as in the original implementation.

[mlouielu]

Thanks for your contribution @ianlini, could you please also help to update the documentation in docs?

[ianlini]

Sure. I will try.

[ianlini]

Did I update the docs correctly?

[mlouielu]

Hi @ianlini , I'm on a break yesterday. Yes, you update the code correctly, I'll accept this commit.

Another thing is, please let your commit message have a capital letter in the first words! Consistent is good for our code!

Many thanks for your contribution, @ianlini .

[mlouielu]

@ianlini, commit message and issue title are different on GitHub, you should also check your commit message in your local git.

If you want to change commit message in your latest commit, use git commit --amend, if you want to change a old commit message, you may need to checkout git rebase -i <your target commit hash>.

ref: https://git-scm.com/book/zh-tw/v1/Git-%E5%B7%A5%E5%85%B7-%E9%87%8D%E5%AF%AB%E6%AD%B7%E5%8F%B2

[ianlini]

I know. Just want to change the title first.
The commit message is actually the title of the PR in your current setting, so I think I won't change the commit I have pushed.