docs(plugin-essentials): Improve install command formatting (#6127)

**What's the problem this PR addresses?**
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Improve doc formatting

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**How did you fix it?**
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Format it

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.yarn/versions/845b0c90.yml

@@ -0,0 +1,7 @@
+releases:
+  "@yarnpkg/plugin-essentials": patch
+
+declined:
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/cli"

packages/plugin-essentials/sources/commands/install.ts

@@ -41,11 +41,11 @@ export default class YarnCommand extends BaseCommand {
 
       - **Fetch:** Then we download all the dependencies if needed, and make sure that they're all stored within our cache (check the value of \`cacheFolder\` in \`yarn config\` to see where the cache files are stored).
 
-      - **Link:** Then we send the dependency tree information to internal plugins tasked with writing them on the disk in some form (for example by generating the .pnp.cjs file you might know).
+      - **Link:** Then we send the dependency tree information to internal plugins tasked with writing them on the disk in some form (for example by generating the \`.pnp.cjs\` file you might know).
 
       - **Build:** Once the dependency tree has been written on the disk, the package manager will now be free to run the build scripts for all packages that might need it, in a topological order compatible with the way they depend on one another. See https://yarnpkg.com/advanced/lifecycle-scripts for detail.
 
-      Note that running this command is not part of the recommended workflow. Yarn supports zero-installs, which means that as long as you store your cache and your .pnp.cjs file inside your repository, everything will work without requiring any install right after cloning your repository or switching branches.
+      Note that running this command is not part of the recommended workflow. Yarn supports zero-installs, which means that as long as you store your cache and your \`.pnp.cjs\` file inside your repository, everything will work without requiring any install right after cloning your repository or switching branches.
 
       If the \`--immutable\` option is set (defaults to true on CI), Yarn will abort with an error exit code if the lockfile was to be modified (other paths can be added using the \`immutablePatterns\` configuration setting). For backward compatibility we offer an alias under the name of \`--frozen-lockfile\`, but it will be removed in a later release.