Finds the grapheme-index of the given search string.
auto t1 = typeof(this)("Test R̆ȧm͆b̪õ R̆ȧm͆b̪õ"); assert(t1.indexOf("ȧ") == 6); assert(t1.indexOf("m̪") == -1);
See Implementation
Finds the grapheme-index of the given search string.