nim.kak: Add auto-indent after tuple and object

Before:
```nim
type
  MyType = tuple
  myint: int     # This line needs to be indented manually
```

After:
```nim
type
  MyType = tuple
    myint: int     # Lines after 'tuple' are now indented automatically
```

rc/filetype/nim.kak

@@ -110,8 +110,8 @@ def -hidden nim-indent-on-new-line %{
         try %{ exec -draft \; K <a-&> }
         # cleanup trailing whitespaces from previous line
         try %{ exec -draft k <a-x> s \h+$ <ret> d }
-        # indent after line ending with type, import, export, const, let, var, ':' or '='
-        try %{ exec -draft <space> k x <a-k> (:|=|const|let|var|import|export|type)$ <ret> j <a-gt> }
+        # indent after line ending with tuple, object, type, import, export, const, let, var, ':' or '='
+        try %{ exec -draft <space> k x <a-k> (:|=|tuple|object|const|let|var|import|export|type)$ <ret> j <a-gt> }
     }
 }