Rename selected configuration profiles to overlays

internal/engine/overlay_test.go

@@ -22,7 +22,7 @@ to_scalar: {child: old}
 	}
 	overlay := parseCompositionDocument(t, "source-2", `shared:
   changed: new
-  added: profile
+  added: overlay
 sequence: []
 nullable: null
 to_map: {child: new}
@@ -42,7 +42,7 @@ to_scalar: scalar
 	}{
 		{path: Keys("shared", "kept"), kind: document.String, text: "base"},
 		{path: Keys("shared", "changed"), kind: document.String, text: "new"},
-		{path: Keys("shared", "added"), kind: document.String, text: "profile"},
+		{path: Keys("shared", "added"), kind: document.String, text: "overlay"},
 		{path: Keys("sequence"), kind: document.Sequence},
 		{path: Keys("nullable"), kind: document.Null},
 		{path: Keys("to_map"), kind: document.Mapping},
@@ -62,7 +62,7 @@ to_scalar: scalar
 		t.Fatal("parent replacement retained a stale child origin")
 	}
 	shared := result.origins["/shared"]
-	if shared.Layer != LayerProfile || len(shared.Locations) != 2 {
+	if shared.Layer != LayerOverlay || len(shared.Locations) != 2 {
 		t.Fatalf("shared mapping origin = %#v", shared)
 	}
 	if len(result.overlays) != 5 {