Typo fixes for Ada mode.

Typo fixes for Ada mode.

* progmodes/ada-mode.el (ada-batch-reformat): Doc fix.
  (ada-create-case-exception): Fix typo in docstring.
  (ada-no-auto-case): Return nil, not the docstring.
  (ada-indent-current): Reflow docstring.

* progmodes/ada-prj.el (ada-prj-edit, ada-prj-initialize-values)
  (ada-prj-save-specific-option, ada-prj-field): Fix typos in docstrings.
  (ada-prj-load-from-file): Reflow docstring.
  (ada-prj-display-page): Fix typo in widget.

* progmodes/ada-stmt.el (ada-case, ada-package-body, ada-private):
  Fix typos in docstrings.

* progmodes/ada-xref.el (ada-find-executable, ada-gnat-parse-gpr)
  (ada-compile-current, ada-check-current, ada-run-application)
  (ada-get-ali-file-name): Fix typos in docstrings.
  (ada-xref-confirm-compile, ada-find-references)
  (ada-find-local-references, ada-find-any-references): Doc fixes.
  (ada-get-all-references): Fix typo in error message.
  (ada-xref-current-project): Use `let', not `let*'.
  (ada-do-file-completion, ada-xref-change-buffer): Reflow docstring.