[clangd] Save an unnecessary copy, NFC.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@372752 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/clangd/FileDistance.cpp b/clangd/FileDistance.cpp
index a6a65ab..a9ce3e5 100644
--- a/clangd/FileDistance.cpp
+++ b/clangd/FileDistance.cpp
@@ -208,7 +208,7 @@
     Param.MaxUpTraversals = std::max(Path.second - 1, 0);
     Sources[Path.first] = std::move(Param);
   }
-  return FileDistance(Sources, Opts);
+  return FileDistance(std::move(Sources), Opts);
 }
 
 ScopeDistance::ScopeDistance(llvm::ArrayRef<std::string> QueryScopes)