Refines a query or filter to match items whose specified property value equals the specified value.
The eq() function refines a WixDataQuery or WixDataFilter to only
match items where the value of the specified property equals the specified value.
It only matches values of the same type. For example, a number value stored as a String type does not match the same number stored as a Number type.
Matching strings with eq() is case sensitive, so "text" is not equal to "Text".
If propertyName points to a collection field of type Array, eq() includes the item
as long as at least one Array element matches the specified value.
The property whose value will be compared with value.
The value to match against.