[clang-tools-extra] [include-cleaner] rename enabled flags to `disable-*` (PR #132991)

[Aaron Ballman via cfe-commits]

================
@@ -183,9 +195,26 @@ class Action : public clang::ASTFrontendAction {
     auto Results =
         analyze(AST.Roots, PP.MacroReferences, PP.Includes, &PI,
                 getCompilerInstance().getPreprocessor(), HeaderFilter);
-    if (!Insert)
+
+    if (!Insert) {
+      llvm::errs()
+          << "[WARNING] -insert is deprecated in favor of `-disable-insert`. "
+             "The old flag was confusing since it suggested that inserts "
+             "were disabled by default, when they were actually enabled. "
+             "See https://github.com/llvm/llvm-project/issues/132983\n";
+    }
+
+    if (!Remove) {
+      llvm::errs()
+          << "[WARNING] -remove is deprecated in favor of `-disable-remove`. "
+             "The old flag was confusing since it suggested that removes "
+             "were disabled by default, when they were actually enabled. "
+             "See https://github.com/llvm/llvm-project/issues/132983\n";
+    }
+
----------------
AaronBallman wrote:

There's one more thing I'd like to see, just as a kindness to user:
```
if (Remove && DisableRemove)
  llvm::errs() << "warning: '-remove=1' and '-disable-remove' are incompatible options\n";
if (Insert && DisableInsert)
  llvm::errs() << "warning: '-insert=1' and '-disable-insert' are incompatible options\n";
```
(And add tests for the diagnostics as well.)

WDYT?

https://github.com/llvm/llvm-project/pull/132991