Update README.md

[shantanu-sardesai]

Hi, I started learning OCaml today and was installing utop when I noticed a minor inconsistency in between the directions given in the utoprc-dark file and the README on the location to store the theme information.

The ones in the utoprc-dark worked for me, so creating a PR to update the path in the README.

[emillon]

No, utop should load the files from the path in README since #431. What version of utop are you using?

[shantanu-sardesai]

Should be the latest one since I Installed it this morning using the command from the README.

A screenshot of my utop version (v2.13.1):

could it be that I misunderstood what the effects of adding the code from utoprc-dark are?

It made some minor changes in the color being displayed in my repl after I pasted the contents in ~/.config/utoprc, didn't do the same when I pasted it in the ~/.config/utop/utoprc first.

Without any configuration:

With configuration in ~/.config/utoprc:

With configuration in ~/.config/utop/utoprc (Same as without configuration):

My utoprc file: