* progmodes/ada-mode.el: Fix bug#1920, bug#5400.

* progmodes/ada-mode.el: Fix bug#1920, bug#5400.
  (ada-ident-re): Delete ., allow multibyte characters.
  (ada-goto-label-re): New; matches goto labels.
  (ada-block-label-re): New; matches block labels.
  (ada-label-re): New; matches both.
  (ada-named-block-re): Deleted; callers changed to use
  `ada-block-label-re' instead.
  (ada-get-current-indent, ada-get-indent-noindent, ada-get-indent-loop):
  Use `ada-block-label-re'.
  (ada-indent-on-previous-lines): Improve handling of goto labels.
  (ada-get-indent-block-start): Special-case block label.
  (ada-get-indent-label): Split into `ada-indent-block-label' and
  `ada-indent-goto-label'.
  (ada-goto-stmt-start, ada-goto-next-non-ws): Optionally ignore goto labels.
  (ada-goto-next-word): Simplify.
  (ada-indent-newline-indent-conditional): Insert newline before
  trying to fix indentation; doc fix.