[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/FixedAddressChecker.cpp b/lib/StaticAnalyzer/Checkers/FixedAddressChecker.cpp
index 531d87e..7bdd4f3 100644
--- a/lib/StaticAnalyzer/Checkers/FixedAddressChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/FixedAddressChecker.cpp
@@ -51,7 +51,7 @@
   if (!RV.isConstant() || RV.isZeroConstant())
     return;
 
-  if (ExplodedNode *N = C.generateNode()) {
+  if (ExplodedNode *N = C.addTransition()) {
     if (!BT)
       BT.reset(new BuiltinBug("Use fixed address", 
                           "Using a fixed address is not portable because that "