Update some missing 4.2 references

Author: wesbland

_config.yml

@@ -27,8 +27,8 @@ navbar-links:
     Docs: "docs/"
     Current MPI Efforts:
         - Implementation Status: implementation-status/
-        - MPI 4.2: "mpi-42/"
         - MPI 5.0: "mpi-50/"
+        - MPI Next: "mpi-next/"
     Meetings:
         - Voting Meetings: "meetings"
         - Non-Voting Meetings: "non_voting_meetings"

index.md

@@ -13,8 +13,8 @@ You may find standard documents, information about the activities of the MPI for
 
 The MPI Forum is currently pursuing at least one future version of the MPI Standard:
 
-* [MPI 4.2](mpi-42/): A standard update following MPI 4.1 with smaller features
 * [MPI 5.0](mpi-50/): A standard update following MPI 4.1 with major new features
+* [MPI Next](mpi-next/): A standard update following MPI 5.0 with currently undefined features
 
 More details can be found in the respective sections.