clang-tidy: fix `modernize-loop-convert` lints
diff --git a/Source/cmIDEOptions.cxx b/Source/cmIDEOptions.cxx
index 5a22697..9468d4a 100644
--- a/Source/cmIDEOptions.cxx
+++ b/Source/cmIDEOptions.cxx
@@ -21,8 +21,8 @@
   this->DoingInclude = false;
   this->AllowSlash = false;
   this->DoingFollowing = nullptr;
-  for (int i = 0; i < FlagTableCount; ++i) {
-    this->FlagTable[i] = nullptr;
+  for (auto& flag : this->FlagTable) {
+    flag = nullptr;
   }
 }