[analyzer] Rename generateNode -> addTransition in CheckerContext

Also document addTransition methods.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp b/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
index 1124242..8a7f48b 100644
--- a/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
@@ -312,7 +312,7 @@
 
     // The result is not consumed by a surrounding expression.  Just propagate
     // the current state.
-    C.generateNode(state);
+    C.addTransition(state);
     return;
   }
 
@@ -349,11 +349,11 @@
     // of this case unless we have *a lot* more knowledge.
     //
     SVal V = C.getSValBuilder().makeZeroVal(msg.getType(Ctx));
-    C.generateNode(state->BindExpr(msg.getOriginExpr(), V));
+    C.addTransition(state->BindExpr(msg.getOriginExpr(), V));
     return;
   }
 
-  C.generateNode(state);
+  C.addTransition(state);
 }
 
 void ento::registerCallAndMessageChecker(CheckerManager &mgr) {