Enhance notes for 'b2' libretro core (per Jamiras)

Updated notes for the 'b2' libretro core regarding console ID, hashing method, and memory map requirements.

Author: Hoff16

docs/developer-docs/unsupported-emulators-and-cores.md

@@ -249,7 +249,7 @@ This is a list of emulators and cores that have either been confirmed to not wor
 
 | Name          | Type          | Status  | Notes         |
 | :------------ | :------------ | :-----: | :------------- |
-| **b2**        | libretro core | ❓ | Testing needed |
+| **b2**        | libretro core | ❓ | - Needs console ID, hashing method and memory map<br>- Memory not exposed |
 
 ## Amiga