Allow to jump to definition of external functions defined in the same module

CHANGELOG.md

@@ -402,6 +402,10 @@
   prelude.
   ([Surya Rose](https://github.com/GearsDatapacks))
 
+- Fixed a bug where the language server wouldn't let you jump to the definition
+  of a function with an external implementation defined in the same module.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
 ## v1.4.1 - 2024-08-04
 
 ### Bug Fixes

compiler-core/schema.capnp

@@ -108,11 +108,11 @@ struct ValueConstructor {
 }
 
 struct Publicity {
-    union {
-        public @0 :Void;
-        private @1 :Void;
-        internal @2 :Option(SrcSpan);
-    }
+  union {
+    public @0 :Void;
+    private @1 :Void;
+    internal @2 :Option(SrcSpan);
+  }
 }
 
 struct Implementations {
@@ -141,6 +141,8 @@ struct ValueConstructorVariant {
       location @7 :SrcSpan;
       documentation @15 :Text;
       implementations @18 :Implementations;
+      externalErlang @20 :Option(External);
+      externalJavascript @21 :Option(External);
     }
 
     record :group {
@@ -156,6 +158,11 @@ struct ValueConstructorVariant {
   }
 }
 
+struct External {
+  module @0 :Text;
+  function @1 :Text;
+}
+
 struct SrcSpan {
   start @0 :UInt32;
   end @1 :UInt32;