feat: add MIME consts

[cqqqq777]

What type of PR is this?

feat

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• This PR title match the format: <type>(optional scope): <description>.
• The description of this PR title is user-oriented and clear enough for others to understand.
• Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo.

(Optional) Translate the PR title into Chinese.

新增 MIME 常量

(Optional) More detail description for this PR(en: English/zh: Chinese).

en: add MIME consts
zh(optional): 新增 MIME 常量

(Optional) Which issue(s) this PR fixes:

#754

(Optional) The PR that updates user documentation:

[cqqqq777]

just add some commonly used MIME types

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (56411f8) 75.66% compared to head (f101d61) 75.66%.

❗ Current head f101d61 differs from pull request most recent head 6735831. Consider uploading reports for the commit 6735831 to get more accurate results

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #776   +/-   ##
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  Coverage    75.66%   75.66%           
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  Files           97       97           
  Lines         9477     9477           
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  Hits          7171     7171           
  Misses        1856     1856           
  Partials       450      450           

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[welkeyever]

Please follow the pr template and complete the information.
Like this: #758

[welkeyever]

LGTM, thx~

[FGYFFFF]

@cqqqq777 The unit test seems to have some MIME content-type strings, would you like to help replace them together?

[cqqqq777]

ok, I need some time.

[cqqqq777]

may be some omissions, because there are too many unit test code

[cqqqq777]

ok

[li-jin-gou]

@cqqqq777 This is great and is what users need right now. But can we provide a document like fiber to help users know that we provide these constants. refer to https://docs.gofiber.io/api/constants .

[cqqqq777]

cloudwego/cloudwego.github.io#657