equals function
Checks if two strings are exactly equal.
Performs a direct string comparison between str and comparison.
This comparison is case-sensitive.
Returns true if the strings are identical, otherwise returns false.
Example:
equals('hello', 'hello'); // true
equals('Hello', 'hello'); // false (case-sensitive)
equals('hello', 'world'); // false
Implementation
bool equals(String str, String comparison) => _equals(str, comparison);