gnu: Synchronize descriptions with the Womb.

Note: some of these changes undo bits of 35b9e423.

* gnu/packages/base.scm, gnu/packages/gperf.scm, gnu/packages/guile.scm,
  gnu/packages/libidn.scm, gnu/packages/miscfiles.scm,
  gnu/packages/telephony.scm: Adjust synopses and descriptions as
  suggested by 'make sync-descriptions'.