[clang] [clang-format] Do not update cursor pos if no includes replacement (PR #77456)

[Owen Pan via cfe-commits]

https://github.com/owenca commented:

`git diff Format.cpp` output:
```
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3116,6 +3116,7 @@ static void sortCppIncludes(const FormatStyle &Style,
     return;
   }
 
+  const auto OldCursor = Cursor ? *Cursor : 0;
   std::string result;
   for (unsigned Index : Indices) {
     if (!result.empty()) {
@@ -3139,6 +3140,8 @@ static void sortCppIncludes(const FormatStyle &Style,
   // the entire range of blocks. Otherwise, no replacement is generated.
   if (replaceCRLF(result) == replaceCRLF(std::string(Code.substr(
                                  IncludesBeginOffset, IncludesBlockSize)))) {
+    if (Cursor)
+      *Cursor = OldCursor;
     return;
   }
 
```

https://github.com/llvm/llvm-project/pull/77456