Add docs for pnpm (#14455)

docs/precommit.md

@@ -42,6 +42,14 @@ yarn add --dev pretty-quick
 yarn husky set .husky/pre-commit "npx pretty-quick --staged"
 ```
 
+<!--pnpm-->
+
+```bash
+pnpm exec husky-init
+pnpm add --save-dev pretty-quick
+pnpm exec husky set .husky/pre-commit "npx pretty-quick --staged"
+```
+
 <!--END_DOCUSAURUS_CODE_TABS-->
 
 Read more at the [pretty-quick](https://github.com/azz/pretty-quick) repo.
@@ -112,6 +120,14 @@ yarn add --dev git-format-staged
 yarn husky set .husky/pre-commit "git-format-staged -f 'prettier --ignore-unknown --stdin --stdin-filepath \"{}\"' ."
 ```
 
+<!--pnpm-->
+
+```bash
+pnpm exec husky-init
+pnpm add --save-dev git-format-staged
+pnpm husky set .husky/pre-commit "git-format-staged -f 'prettier --ignore-unknown --stdin --stdin-filepath \"{}\"' ."
+```
+
 <!--END_DOCUSAURUS_CODE_TABS-->
 
 Add or remove file extensions to suit your project. Note that regardless of which extensions you list formatting will respect any `.prettierignore` files in your project.