[clang-tidy] Show 'allow-enabling-analyzer-alpha-checkers' flag in '--help' command.

[vbvictor]

In clang-tidy, we have an option allow-enabling-analyzer-alpha-checkers that is not visible to users.

llvm-project/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp

Lines 278 to 284 in b6313b3

	/// This option allows enabling the experimental alpha checkers from the static
	/// analyzer. This option is set to false and not visible in help, because it is
	/// highly not recommended for users.
	static cl::opt<bool>
	AllowEnablingAnalyzerAlphaCheckers("allow-enabling-analyzer-alpha-checkers",
	cl::init(false), cl::Hidden,
	cl::cat(ClangTidyCategory));

I don't see a reason why it is invisible for users.

How can a user find out about the opportunity of running analyzer-alpha-checkers without reading source code?
I believe there are people like me who could benefit from seeing this option in regular --help documentation.

Moreover, the allow-enabling-analyzer-alpha-checkers option is presented in run-clang-tidy:

llvm-project/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py

Lines 298 to 301 in b6313b3

	parser.add_argument(
	"-allow-enabling-alpha-checkers",
	action="store_true",
	help="Allow alpha checkers from clang-analyzer.",

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Baranov Victor (vbvictor)

In clang-tidy, we have an option `allow-enabling-analyzer-alpha-checkers` that is not visible to users. https://github.com/llvm/llvm-project/blob/b6313b381ac0e83012ea11b4549cd8cb39b686d2/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp#L278-L284 I don't see a reason why it is invisible for users.

How can a user find out about the opportunity of running analyzer-alpha-checkers without reading source code?

I believe there are people like me who could benefit from seeing this option in regular --help documentation.

Moreover, the allow-enabling-analyzer-alpha-checkers option is presented in run-clang-tidy:

llvm-project/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py

Lines 298 to 301 in b6313b3

	parser.add_argument(
	"-allow-enabling-alpha-checkers",
	action="store_true",
	help="Allow alpha checkers from clang-analyzer.",

[carlosgalvezp]

It says "it's highly not recommended for users". Would be good to figure out more about this, maybe we can find the original author and ask? We'll need to put this info in the help of the flag.