bug#35353: 26.2; Buffer *xref*: (1) hard-coded mouse-1, (2) major mode name

[Drew Adams <drew.adams@oracle.com>]

Never bothered to use Xref (`dired-do-find-regexp' etc.) until now.
I'm already surprised at what I see within the first 3 minutes.

1. I use `mouse-1-click-follows-link' = nil.  (I use `mouse-2', not
   `mouse-1', to follow clicked links, buttons, etc.)  But this
   setting seems to have no effect in buffer `*xref*'.

   Except by clicking on a file line (it seems), I find it impossible
   to click `mouse-1' without having Emacs follow a link; impossible
   to set point in the buffer using `mouse-1'; no way to just click
   buffer text to select its frame.  What's that all about? 

2. I try `C-h m' or `C-h v major-mode' to find out more about what's
   going on, and I learn that the major mode is called
   `xref--xref-buffer-mode'.  Seriously?  Why?  It seems very wrong
   and unEmacsy to give a major mode an "internal" name.  Users
   examine major modes.  That's part of the usual help system for
   even casual users.

Please respect `mouse-1-click-follows-link'.  And please name the
major mode without an "internal-function" name.  Thx.


In GNU Emacs 26.2 (build 1, x86_64-w64-mingw32)
 of 2019-04-13
Repository revision: fd1b34bfba8f3f6298df47c8e10b61530426f749
Windowing system distributor `Microsoft Corp.', version 10.0.17134
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''