docs: improve the npx description clarity (#6102)

docs/guide/index.md

@@ -37,9 +37,9 @@ bun add -D vitest
 Vitest 1.0 requires Vite >=v5.0.0 and Node >=v18.0.0
 :::
 
-It is recommended that you install a copy of `vitest` in your `package.json`, using one of the methods listed above. However, if you would prefer to run `vitest` directly, you can use `npx vitest` (the `npx` command comes with npm and Node.js).
+It is recommended that you install a copy of `vitest` in your `package.json`, using one of the methods listed above. However, if you would prefer to run `vitest` directly, you can use `npx vitest` (the `npx` tool comes with npm and Node.js).
 
-The `npx` command will execute the command either from a local `node_modules/.bin` installing any packages needed in order for the command to run. By default, npx will check whether command exists in $PATH, or in the local project binaries, and execute that. If command is not found, it will be installed prior to execution.
+The `npx` tool will execute the specified command. By default, `npx` will first check if the command exists in the local project's binaries. If it is not found there, `npx` will look in the system's $PATH and execute it if found. If the command is not found in either location, `npx` will install it in a temporary location prior to execution.
 
 ## Writing Tests