Enable clangd support #4860

Job	Run time
Enzyme CI LLVM 11 Release macOS	24s
Enzyme CI LLVM 11 Release ubuntu-20.04	4m 10s
Enzyme CI LLVM 11 Debug macOS	24s
Enzyme CI LLVM 11 Debug ubuntu-20.04	3m 45s
Enzyme CI LLVM 12 Release macOS	11m 40s
Enzyme CI LLVM 12 Release ubuntu-20.04	4m 34s
Enzyme CI LLVM 12 Debug macOS	1m 34s
Enzyme CI LLVM 12 Debug ubuntu-20.04	4m 1s
Enzyme CI LLVM 13 Release macOS	6m 26s
Enzyme CI LLVM 13 Release ubuntu-20.04	4m 11s
Enzyme CI LLVM 13 Debug macOS	4m 47s
Enzyme CI LLVM 13 Debug ubuntu-20.04	3m 57s
Enzyme CI LLVM 14 Release macOS	6m 44s
Enzyme CI LLVM 14 Release ubuntu-20.04	4m 14s
Enzyme CI LLVM 14 Debug macOS	6m 3s
Enzyme CI LLVM 14 Debug ubuntu-20.04	3m 54s
Enzyme CI LLVM 15 Release macOS	6m 7s
Enzyme CI LLVM 15 Release ubuntu-20.04	4m 21s
Enzyme CI LLVM 15 Debug macOS	5m 53s
Enzyme CI LLVM 15 Debug ubuntu-20.04	4m 14s
Enzyme CI LLVM 16 Release ubuntu-20.04	4m 17s
Enzyme CI LLVM 16 Debug ubuntu-20.04	4m 5s
Enzyme CI LLVM 13 Release macOS XCode	8m 13s
	1h 47m 58s

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