start-manual.sh: Drop explicit pwd's

Dependencies

• [2] 4IVC7COB manual: document working on docs

Change contents

• replacement in foreman/start-manual.sh at line 5
  [2.292]→[2.292:354](∅→∅)
  − --dest-dir $(pwd)/.hydra-data/manual \

  − $(pwd)/doc/manual/
  [2.292]
  + --dest-dir ./.hydra-data/manual \

  + ./doc/manual/