Rename base into language.

_CoqProject

@@ -8,7 +8,7 @@
 # We have ambiguous paths and so far it is not even clear what they are (https://gitlab.mpi-sws.org/iris/iris/issues/240).
 -arg -w -arg -ambiguous-paths
 
-theories/base.v
+theories/language.v
 theories/types.v
 theories/typed.v
 theories/sem_types.v

theories/sem_types.v

-From tutorial_popl20 Require Export base.
+From tutorial_popl20 Require Export language.
 From iris.heap_lang Require Export proofmode.
 From iris.base_logic.lib Require Export invariants.
 

theories/types.v

-From tutorial_popl20 Require Export base.
+From tutorial_popl20 Require Export language.
 
 Inductive ty :=
   | TVar : nat → ty