Fix Agda RPC for upcoming 2.8.0

agda/agda#7610 changed the RPC for `Interval` types which broke
cornelis. We're making a change before 2.8.0 is released so we'll be
ready on release day.

Author: 4e554c4c

src/Cornelis/Offsets.hs

@@ -130,7 +130,7 @@ data Interval p = Interval { iStart, iEnd :: !p }
 
 instance Show p => Show (Interval p) where
   showsPrec n (Interval s e) =
-    showParen (n >= 11) $ showString "Interval " . showsPrec 11 s . showSpace . showsPrec 11 e
+    showParen (n >= 11) $ showString "Interval () " . showsPrec 11 s . showSpace . showsPrec 11 e
 
 -- Common specializations
 

stack.yaml

@@ -1,6 +1,6 @@
-# GHC 9.6.4
+# GHC 9.8.4
 # Update `defaultGHCVersion` in `./flake.nix` when updating to resolver with different GHC version.
-resolver: lts-22.13
+resolver: lts-23.9
 
 packages:
 - .

stack.yaml.lock

@@ -1,7 +1,7 @@
 # This file was autogenerated by Stack.
 # You should not edit this file by hand.
 # For more information, please see the documentation at:
-#   https://docs.haskellstack.org/en/stable/lock_files
+#   https://docs.haskellstack.org/en/stable/topics/lock_files
 
 packages:
 - completed:
@@ -13,7 +13,7 @@ packages:
     hackage: levenshtein-0.2.1.0
 snapshots:
 - completed:
-    sha256: 6f0bea3ba5b07360f25bc886e8cff8d847767557a492a6f7f6dcb06e3cc79ee9
-    size: 712905
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/13.yaml
-  original: lts-22.13
+    sha256: 04c9d37f2a00c2bd51bf6b25eb98872059bc58f225d50b5f306ac58f760a178c
+    size: 680567
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/9.yaml
+  original: lts-23.9