libdl.sh.at: Enhance 'dl_meta get' inquiries test
libdl.sh.at: Enhance 'dl_meta get' inquiries test

This involves:
  - Add a detailed description
  - Move expected output from AT_DATA() invocation to 3rd argument of
    AT_CHECK() invocation
  - Drop leading '#'s from tag emissions
  - Double some brackets in expected output to avoid underquoting

donkarlos/libdl-sh