add branch support to Go

Author: josharian

queries/go.scm

@@ -222,3 +222,32 @@
     .
   )
 ) @anonymousFunction @namedFunction
+
+(
+  [
+    (default_case)
+    (expression_case)
+    (type_case)
+  ] @branch
+
+  ;; TODO: insertion delimiters snafu
+
+  ;; The following is almost right, for drink and pour,
+  ;; although it would be best if the cursor was just before the colon.
+  ;; It also has some leading whitespace problems.
+  ;;
+  (#insertion-delimiter! @branch "case :\n\n")
+
+  ;; This one is right for clone.
+  ;; (#insertion-delimiter! @branch "")
+)
+
+[
+  (type_switch_statement)
+  (expression_switch_statement)
+] @branch.iteration
+
+;; TODO: if-then-else branches? They're rare in Go.
+;; TODO: in `case x, y, z:`, should x/y/z be values? names?
+;; what about type switch cases: should they be types?
+;; TODO: teach condition about switch statement conditions