Log Message:
tmux: Update to 3.5a

Changes:
CHANGES FROM 3.5 TO 3.5a

* Do not translate BSpace as Unicode with extended keys.
* Fix so that keys with Shift are represented correctly with extended keys.
* Revert to using /bin/sh for #() and run-shell and if-shell; the change to use
  default-shell only applies now to popups.
* Fix grey colour without a number suffix in styles.

CHANGES FROM 3.4 TO 3.5

* Revamp extended keys support to more closely match xterm and support mode 2
  as well as mode 1. This is a substantial change to key handling which changes
  tmux to always request mode 2 from parent terminal, changes to an unambiguous
  internal representation of keys, and adds an option (extended-keys-format) to
  control the format similar to the xterm(1) formatOtherKeys resource.
* Clear an overlay (popup or menu) when command prompt is entered.
* Add copy-mode -d flag to scroll a page down if in copy mode already (matching
  -e).
* Display hyperlinks in copy mode and add copy_cursor_hyperlink format to get
  the hyperlink under the cursor.
* Add a prefix timeout option.
* Mouse move keys are not useful as key bindings because we do not turn them on
  unless the application requests them. Ignore them so they do not cause the
  prefix to be canceled
* Add search_count and search_count_partial formats in copy mode.
* Do not reset mouse pane if clicked on status line,
* Add mirrored versions of the main-horizontal and main-vertical layouts where
  the main pane is bottom or right instead of top or left.
* Allow REP to work with Unicode characters.
* Fix size calculation of terminators for clipboard escape sequences.
* Treat CRLF as LF in config files where it is easy to do so.
* The Linux console has some bugs with bright colours, so add some workarounds
  for it.
* If built with systemd, remove some environment variables it uses.
* Adjust the logic when deleting last buffer to better preserve the selection:
  if selecting the element below the deleted one fails (because as the last
  one), select the one above it instead.
* Add --enable-jemalloc to build with jemalloc memory allocator (since glibc
  malloc is so poor).
* Add a way (refresh-client -r) for control mode clients to provide OSC 10 and
  11 responses to tmux so they can set the default foreground and background
  colours.
* Add N to search backwards in tree modes.
* Use default-shell for command prompt, #() and popups.
* Revert part of a change intended to improve search performance by skipping
  parts of lines already searched, but which in fact skipped the ends of lines
  altogether.
* Add a command-error hook when a command fails.
* Add an option allow-set-title to forbid applications from changing the pane
  title.
* Correct handling of mouse up events (don't ignore all but the last released
  button), and always process down event for double click.
* Fix a crash if focusing a pane that is exiting.
* Pick newest session (as documented) when looking for next session for
  detach-on-destroy.
* Reduce default escape-time to 10 milliseconds.
* Add display-menu -M to always turn mouse on in a menu.
* Look for feature code 21 for DECSLRM and 28 for DECFRA in the device
  attributes and also accept level 1.
* Fix crash if built with SIXEL and the SIXEL colour register is invalid; also
  remove SIXEL images before reflow.
* Do not notify window-layout-changed if the window is about to be destroyed.
* Do not consider a selection present if it is empty for the selection_active
  and selection_present format variables.
* Fix split-window -p.