[clang] [clang-tools-extra] [clangd][clang-tidy] Factor out mergeFixits() logic and reuse it in clangd (PR #208682)

[Zeyi Xu via cfe-commits]

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@@ -165,6 +165,7 @@ clang_target_link_libraries(clangDaemon
   clangBasic
   clangDependencyScanning
   clangDriver
+  clangEdit
----------------
zeyi2 wrote:

I'm slightly concerned about adding a new `clangEdit` dependency for this. Since the change itself is fairly small, could we avoid introducing the dependency, especially if it may affect build times?

I'd also be interested in hearing what the clangd folks think about this.

https://github.com/llvm/llvm-project/pull/208682