Preserve wrap state across change-preview-window

toggle-preview-wrap (and -wrap-word) modifies t.activePreviewOpts.wrap,
but change-preview-window resets t.previewOpts to t.initialPreviewOpts,
discarding the user's toggle. Carry wrap and wrapWord over so toggles
survive a layout change. Explicit wrap / nowrap tokens in the new spec
still win, so cycling and the empty-token reset are unaffected.

Close #4791

CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+0.73.0
+------
+- Bug fixes
+    - `change-preview-window` no longer resets `wrap` / `wrap-word` state set via `toggle-preview-wrap` / `toggle-preview-wrap-word`. Layout fields still snap to the preset, so cycling and the empty-token reset behave as before. The new spec can still override by including `wrap` or `nowrap` explicitly. (#4791)
+
 0.72.0
 ------
 _Release highlights: https://junegunn.github.io/fzf/releases/0.72.0/_