Add to docs where to create the reset.d.ts file

[frdwhite24]

Thanks for the fantastic library! I always install it on new projects and I love your work.

Context of issue: Every time I start a new project, it's just infrequently enough that I forget how I set things up beforehand. Every time I install the lib and then include the reset.d.ts in my project root, it doesn't work. It always takes me about 30 mins to go through the debugging process before I remember that I need to move it to ./src/reset.d.ts rather than just in the project root amongst all the .prettierrc / .eslintrc files.

Proposed solution: Add in a statement about WHERE to create the reset.d.ts file in your getting started steps, or at least a troubleshooting section which covers the topic of where you might need to put it to get it to work / common setup problems.