Add -explain-module-dependency-detailed new driver flag.

This flag will be used to have the driver print out all possible paths to the argument dependency module name. `-explain-module-dependency` will print the first discovered such path, in order to produce an answer sooner.

Author: artemcm

include/swift/Option/Options.td

@@ -1398,7 +1398,11 @@ def disable_clang_target : Flag<["-"], "disable-clang-target">,
 
 def explain_module_dependency : Separate<["-"], "explain-module-dependency">,
   Flags<[NewDriverOnlyOption]>,
-  HelpText<"Emit remark/notes describing why compilation may depend on a module with a given name.">;
+  HelpText<"Emit remark describing why compilation may depend on a module with a given name.">;
+
+def explain_module_dependency_detailed : Separate<["-"], "explain-module-dependency-detailed">,
+  Flags<[NewDriverOnlyOption]>,
+  HelpText<"Emit remarks describing every possible dependency path that explains why compilation may depend on a module with a given name.">;
 
 def explicit_auto_linking : Flag<["-"], "explicit-auto-linking">,
   Flags<[NewDriverOnlyOption]>,