[READY] Add support for DocumentSymbol in document outline requests #766

Job	Run time
C++ Lint	6m 12s
Windows MSVC 17 x64 - C++ Benchmark	3m 52s
Windows MSVC 17 x64 - test run	1m 56s
ubuntu-24.04 - C++ Benchmark	2m 5s
ubuntu-24.04 - test run	1m 35s
Windows MSVC 17 x86 - test run	1m 51s
macos-14 - C++ Benchmark	1m 45s
macos-14 - test run	1m 16s
Windows MSVC 16 x64 - test run	2m 8s
ubuntu-24.04 - with Clang compiler - test run	1m 27s
ubuntu-24.04 - without libclang completer - test run	1m 34s
	25m 41s

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