Function isString

isString(value): value is string
Determines whether the provided value is a string.

This function checks if the provided value is of type "string" or an instance of the String object. It is used to validate if the value can be used as a string.
Parameters
- value: unknown
  
  The value to be checked.
Returns value is string
true if the value is a string, otherwise false.
Example
```
// Returns: true
ix.api.is.isString("Hello, World!");

// Returns: false
ix.api.is.isString(123);
```