[clangd] Consistent precedence between --header-insertion and HeaderInsertion (#146235)

In PR #128503, the CLI option would take precedence over the config option
only if it was set to `never`. This commit ensures the CLI option always takes
precedence over the config option.

Author: MythreyaK

clang-tools-extra/clangd/tool/ClangdMain.cpp

@@ -668,7 +668,6 @@ class FlagsConfigProvider : public config::Provider {
     std::optional<Config::ExternalIndexSpec> IndexSpec;
     std::optional<Config::BackgroundPolicy> BGPolicy;
     std::optional<Config::ArgumentListsPolicy> ArgumentLists;
-    std::optional<Config::HeaderInsertionPolicy> HeaderInsertionPolicy;
 
     // If --compile-commands-dir arg was invoked, check value and override
     // default path.
@@ -713,11 +712,6 @@ class FlagsConfigProvider : public config::Provider {
       BGPolicy = Config::BackgroundPolicy::Skip;
     }
 
-    // If CLI has set never, use that regardless of what the config files have
-    if (HeaderInsertion == Config::HeaderInsertionPolicy::NeverInsert) {
-      HeaderInsertionPolicy = Config::HeaderInsertionPolicy::NeverInsert;
-    }
-
     if (std::optional<bool> Enable = shouldEnableFunctionArgSnippets()) {
       ArgumentLists = *Enable ? Config::ArgumentListsPolicy::FullPlaceholders
                               : Config::ArgumentListsPolicy::Delimiters;
@@ -732,8 +726,8 @@ class FlagsConfigProvider : public config::Provider {
         C.Index.Background = *BGPolicy;
       if (ArgumentLists)
         C.Completion.ArgumentLists = *ArgumentLists;
-      if (HeaderInsertionPolicy)
-        C.Completion.HeaderInsertion = *HeaderInsertionPolicy;
+      if (HeaderInsertion.getNumOccurrences())
+        C.Completion.HeaderInsertion = HeaderInsertion;
       if (AllScopesCompletion.getNumOccurrences())
         C.Completion.AllScopes = AllScopesCompletion;