docs(generics): explain use of wildcards (?) for flexible type handling in Java

- Added documentation describing wildcards as placeholders for unknown types in generics.
- Clarified that wildcards allow looser type definitions and increase flexibility when exact type is not known at declaration.
- Highlighted practical use cases:
  • Writing methods/classes that can work with a wider range of types.
  • Allowing read-only access when modifying is unsafe (e.g., List<?>).
  • Supporting inheritance scenarios where covariance/contravariance applies.

This improves conceptual understanding of how wildcards differ from concrete type parameters
and why they are essential for designing reusable, type-safe APIs.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section24JavaGenerics/src/WildcardsInGenerics/Wildcards.txt

@@ -0,0 +1,8 @@
+In Java Generics, wildcards (?) are a special kind of type argument that can be used in method arguments or class
+definitions to represent an unknown type.
+
+They allow for more flexible and dynamic code by letting the type be specified later or be more loosely
+defined.
+
+Wildcards are useful when you don’t know the exact type at the time of defining a class or method, or when you want to
+allow a range of types rather than a single specific one.