[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/DivZeroChecker.cpp b/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
index 3bae92b..75b7cc4 100644
--- a/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
@@ -73,7 +73,7 @@
 
   // If we get here, then the denom should not be zero. We abandon the implicit
   // zero denom case for now.
-  C.generateNode(stateNotZero);
+  C.addTransition(stateNotZero);
 }
 
 void ento::registerDivZeroChecker(CheckerManager &mgr) {