[clang-tools-extra] [clangd] Add CodePatterns config option under Completion (PR #137613)

[Nathan Ridge via cfe-commits]

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@@ -267,6 +267,17 @@ opt<Config::HeaderInsertionPolicy> HeaderInsertion{
             "Never insert #include directives as part of code completion")),
 };
 
+opt<Config::CodePatternsPolicy> CodePatterns{
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HighCommander4 wrote:

We've been moving towards having configuration specified only in the config file, not on the command line.

In the few cases where an option exists in both places (e.g. `--function-arg-placeholders`), it's because the command-line argument pre-dated the introduction of the config file system, and was kept for backward-compatibility.

https://github.com/llvm/llvm-project/pull/137613