fixes #11953; jsondoc creates no files unless the htmldocs dir is created (#20198)

* fixes #11953; jsondoc creates no files unless the htmldocs dir is created

* target

* fixes runner

compiler/docgen.nim

@@ -1617,6 +1617,8 @@ proc writeOutputJson*(d: PDoc, useWarning = false) =
   if optStdout in d.conf.globalOptions:
     write(stdout, $content)
   else:
+    let dir = d.destFile.splitFile.dir
+    createDir(dir)
     var f: File
     if open(f, d.destFile, fmWrite):
       write(f, $content)