cpack: Add CLI argument spell checking

Use Levenshtein distance to track when the user may have made a typo in
an argument to `cpack`.

Source/CPack/cpack.cxx

@@ -265,6 +265,11 @@ int main(int argc, char const* const* argv)
     }
     if (!matched && cmHasPrefix(arg, '-')) {
       std::string error = cmStrCat("Unknown argument: ", arg);
+      std::string const suggestion =
+        cmFindClosestCommandLineArgument(arg, arguments);
+      if (!suggestion.empty()) {
+        error = cmStrCat(error, ". Did you mean: ", suggestion, '?');
+      }
       cmCPack_Log(&log, cmCPackLog::LOG_ERROR, error << '\n');
       parsed = false;
     }

Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake

@@ -7,6 +7,7 @@ set(CPACK_PACKAGE_VERSION "1")
 ]])
 set(RunCMake_TEST_NO_CLEAN 1)
 run_cmake_command(NotAGenerator ${CMAKE_CPACK_COMMAND} -G NotAGenerator)
+run_cmake_command(UnknownArgumentDidYouMean ${CMAKE_CPACK_COMMAND} --verbos)
 unset(RunCMake_TEST_NO_CLEAN)
 
 function(run_MultiConfig)

Tests/RunCMake/CPackCommandLine/UnknownArgumentDidYouMean-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/CPackCommandLine/UnknownArgumentDidYouMean-stderr.txt

@@ -0,0 +1 @@
+^CPack Error: Unknown argument: --verbos\. Did you mean: --verbose\?