[user-guide] (12 commits) ...Fix merge conflicts

[Florian Nadge]

Summary of changes:

  e3eeca2... branch for f15 (*)
  878a439... Update po and pot (*)
  fa224aa... Add .tx/config (*)
  6579943... Sync PO files for all available languages (*)
  a8fe4a9... Merge branch 'master' into f16 (*)
  26904c6... Sync PO files with Tx (*)
  1f0c1cc... Update POT files (*)
  8ecbec0... Merge branch 'master' into f16 (*)
  3d05be6... Update POT files (*)
  e017117... Sync PO files with Tx (*)
  a23417f... Proofread chapters, checked titles for correct spelling, ed (*)
  ef6574f... Fix merge conflicts (*)

(*) This commit already existed in another branch; no separate mail sent