[Docs] fix doc typos

[ryan-minato]

Motivation

The English version of the document differs from the Chinese content, and it appears that the Chinese version contains typos caused by using Pinyin.

Modification

"涵盖了模型直接绝大多数的差异" -> "涵盖了模型之间绝大多数的差异"

English edition:
"backbone: usually a feature extraction network that records the major differences between models, e.g., ResNet, MobileNet."

Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects, like MMDet or MMSeg.
• CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

All committers have signed the CLA.