typos suggestion

[ccoVeille]

Check list

• [X] I have performed a self-review of my code
• [ ] I have commented my code in hard-to-understand areas
• [X] I have made corresponding changes to the documentation

Description

• Fix some typos and wordings in README.md
• Fix headers style
• Fix exemplī grātiā usage (Latin)

Type of change

• [ ] Bug fix
• [ ] New feature
• [ ] Refactor
• [ ] Breaking change
• [X] Documentation change

Test environment

• Shell
  • [ ] bash
  • [ ] zsh
  • [ ] fish
• OS
  • [ ] Linux
  • [ ] Mac OS X
  • [ ] Windows
  • [ ] Others:

[carlfriedrich]

@ccoVeille Thanks for your contribution, looks good to me.