doc: hacking: remove duplicate 'by default'

Dependencies

• [2] 4IVC7COB manual: document working on docs
• [3] BZQQZDPL doc: document how to run tests
• [4] DWMH6NFB docs: mention foreman under hacking
• [*] 3JXCTKEC Add markdown files for documentation

Change contents

• replacement in doc/manual/src/hacking.md at line 62
  [2.134]→[2.134:204](∅→∅)
  − at [http://localhost:63332/](http://localhost:63332/) by default, and
  [2.134]

  [2.204]
  + at [http://localhost:63332/](http://localhost:63332/), and