Bind RET in Log View mode to a command that toggles a more detailed display.

Bind RET in Log View mode to a command that toggles a more detailed display.

* lisp/vc/log-view.el: New command log-view-toggle-entry-display for
toggling log entries between concise and detailed forms.
(log-view-toggle-entry-display): New command.
(log-view-mode-map): Bind RET to it.
(log-view-expanded-log-entry-function): New variable.
(log-view-current-entry, log-view-inside-comment-p)
(log-view-current-tag): New functions.
(log-view-toggle-mark-entry): Use log-view-current-entry and
log-view-end-of-defun instead of searching directly with
log-view-message-re.
(log-view-end-of-defun): Likewise.  Add optional ARG for
compatibility with end-of-defun.
(log-view-end-of-defun): Ignore comments and VC buttons.

* lisp/vc/vc-bzr.el (vc-bzr-expanded-log-entry): New function.
(vc-bzr-log-view-mode): Use log-view-expanded-log-entry-function.