[WIP]docs: add FAQ & modify transform overview

[interstellarmt]

Checklist

• npm test passes
• benchmarks are included
• commit message follows commit guidelines
• documents are updated

Description of change

• 增加FAQ，统一FAQ格式
  

• 增加排名趋势图示例
  

• 修改转换 概览文档

[coveralls]

Pull Request Test Coverage Report for Build 14327180981

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 6 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.005%) to 86.773%

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Files with Coverage Reduction	New Missed Lines	%
src/transform/utils/helper.ts	1	92.5%
src/utils/helper.ts	5	90.0%

Totals
Change from base Build 14239476232:	0.005%
Covered Lines:	10733
Relevant Lines:	11989

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💛 - Coveralls