feat: R super assignment textobjects (#448)

Author: fbearoff

queries/r/textobjects.scm

@@ -106,3 +106,17 @@
 
 (equals_assignment
   name: (_) @assignment.inner)
+
+(super_assignment
+  name: (_) @assignment.lhs
+  value: (_) @assignment.inner @assignment.rhs) @assignment.outer
+
+(super_assignment
+  name: (_) @assignment.inner)
+
+(super_right_assignment
+  value: (_) @assignment.inner @assignment.lhs
+  name: (_) @assignment.rhs) @assignment.outer
+
+(super_right_assignment
+  name: (_) @assignment.inner)