Security analysis annotations

`@psalm-taint-source <taint-type>`

See Custom taint sources.

`@psalm-taint-sink <taint-type> <param-name>`

See Custom taint sinks.

`@psalm-taint-escape <taint-type #conditional>`

See Escaping tainted output.

`@psalm-taint-unescape <taint-type>`

See Unescaping statements.

`@psalm-taint-specialize`

See Specializing taints in functions and Specializing taints in classes.

`@psalm-flow [proxy <function-like>] ( <arg>, [ <arg>, ] ) [ -> return ]`