docs: fix process.getSystemVersion() type (#20736)

docs/api/process.md

@@ -217,11 +217,15 @@ that all statistics are reported in Kilobytes.
 
 Returns `String` - The version of the host operating system.
 
-Examples:
+Example:
 
-* `macOS` -> `10.13.6`
-* `Windows` -> `10.0.17763`
-* `Linux` -> `4.15.0-45-generic`
+```js
+const version = process.getSystemVersion()
+console.log(version)
+// On macOS -> '10.13.6'
+// On Windows -> '10.0.17763'
+// On Linux -> '4.15.0-45-generic'
+```
 
 **Note:** It returns the actual operating system version instead of kernel version on macOS unlike `os.release()`.