Found single-character string literal pattern RS-P1100

Certain str functions, such as .split() and .find() work on patterns that accept both string literals as well as characters. When using such functions, prefer chars over single-character string literals as they are more performant.

Replace the single-character string literal with a char.

Bad practice

let x = "hello, world";
x.find("o"); // single-character str

Recommended

let x = "hello, world";
x.find('o'); // use a char instead