private String detectConversionSpecifier(char c) {
		String conversionSpecifierSet = "diuofeaFEApcsxXgGnCS";
		return conversionSpecifierSet.indexOf(c) != -1 ? Character.toString(c) : null;
	}
Skips a series of numbers (field width or precision) within a format String.
returns the index of the format String at the last digit before another
non-digit character

@param formatString format String
@param i      index into formatStr
@return new index into formatString
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/plugin/core/string/variadic/FormatStringParser.java