Allocgate 2.0 slain (#791)

* Allocgate 2.0 slain

* Tests now compile, but they fail

* Temporary bruteforce

tests/helper.zig

@@ -105,7 +105,7 @@ pub fn collectReplacePlaceholders(allocator: std.mem.Allocator, source: []const
 
     return CollectPlaceholdersResult{
         .locations = locations,
-        .new_source = new_source.toOwnedSlice(allocator),
+        .new_source = try new_source.toOwnedSlice(allocator),
     };
 }