- get rid of Designator terminology

SVN=111696

doc/go_lang.txt

@@ -1137,13 +1137,14 @@ Assignments
 ----
 
   Assignment = SingleAssignment | TupleAssignment | Send .
-  SimpleAssignment = Designator assign_op Expression .
-  TupleAssignment = DesignatorList assign_op ExpressionList .
+  SingleAssignment = PrimaryExpr assign_op Expression .
+  TupleAssignment = PrimaryExprList assign_op ExpressionList .
+  PrimaryExprList = PrimaryExpr { "," PrimaryExpr } .
   Send = '>' Expression '=' Expression .
   
   assign_op = [ add_op | mul_op ] '=' .
 
-The designator must be an l-value such as a variable, pointer indirection,
+The left-hand side must be an l-value such as a variable, pointer indirection,
 or an array indexing.
 
   x = 1
@@ -1189,7 +1190,7 @@ must denote a channel pointer value.
 
   >chan_ptr = value
   
-In assignments, the type of the expression must match the type of the designator.
+In assignments, the type of the expression must match the type of the left-hand side.
 
 
 Go statements