#443 Various small documentation updates for 6.0

[Jean-Christophe Helary]

Various small documentation updates

  - add translation conflict resolution section
  https://sourceforge.net/p/omegat/documentation/429/
  - Reference to access tokens
  https://sourceforge.net/p/omegat/documentation/423/
  - Add information about language codes, and format reference.
  https://sourceforge.net/p/omegat/documentation/421/
  - Segmentation rules file name is now segmentation.srx
  https://sourceforge.net/p/omegat/documentation/428/
  - Add warning about creating a project on a network drive
  https://sourceforge.net/p/omegat/documentation/418/
  - Remove "temporarily" from Editor > Enter new segment option.
  - fix duplicate "ID" in XML set
  https://sourceforge.net/p/omegat/documentation/419/

[Jean-Christophe Helary]

https://github.com/omegat-org/omegat/pull/1266