ui: yield unchanged values in walkconfig Ever since walkconfig was introduced back in 25e7ea0f2cff, the values yielded has been mutated by replacing "\n" with "\\n". This makes walkconfig less useful than it could and there is no other way to iterate over all config sections. The third-party reposettings extension used ui.walkconfig but did not take the replacement into account -- this change will actually fix a bug in the extension when a value contains a newline.