[Docs] Modify mdformat setting and refine tables in docs

[Ben-Louis]

Motivation

Update mdformat setting using mdformat-openmmlab. Ruby dependency has been removed in #1382

Modification

• Modify mdformat setting according to https://github.com/open-mmlab/mdformat-openmmlab in .pre-commit-config.yaml
• Reformat tables in docs

BC-breaking (Optional)

Use cases (Optional)

Checklist

Before PR:

• I have read and followed the workflow indicated in the CONTRIBUTING.md to create this PR.
• Pre-commit or linting tools indicated in CONTRIBUTING.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit tests to ensure correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• CLA has been signed and all committers have signed the CLA in this PR.

[codecov]

Codecov Report

Merging #1426 (bf17b8f) into master (4f5ec97) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1426   +/-   ##
=======================================
  Coverage   84.35%   84.35%           
=======================================
  Files         232      232           
  Lines       19279    19279           
  Branches     3468     3468           
=======================================
  Hits        16262    16262           
  Misses       2152     2152           
  Partials      865      865           

Flag	Coverage Δ
unittests	84.28% <ø> (ø)

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