Provide information on how `esbuild` and `esbuild-loader` are different

[burhanuday]

Running this config with esbuild-loader would not be the same as compiling with esbuild as shown on the readme on the project's GitHub - https://github.com/privatenumber/esbuild-loader#why-am-i-not-getting-a-100x-speed-improvement-as-advertised Adding this would clarify on how the two are different