fix: keep location history registered after a savehist setq

A one-time add-to-list put wttrin--location-history into savehist-additional-variables when savehist loaded. Any user who later setqs that list, a common config pattern for curating which histories persist, replaces it and drops the entry. The search history then silently never saves.

Re-assert the registration on savehist-save-hook, which runs at the top of every savehist-save. The variable is now in the list whenever a save happens, regardless of init order or a clobbering setq. Restore was never affected, since savehist reloads the value from explicit setq forms in its file.

The README persistence note now reflects this: the variable stays registered even if you set savehist-additional-variables yourself.

1 files changed, 9 insertions, 1 deletions

diff --git a/wttrin.el b/wttrin.el
index f9d10f0..150e934 100644
--- a/wttrin.el
+++ b/wttrin.el
@@ -509,9 +509,17 @@ Persisted across sessions via `savehist-mode'.")
 ;; Declared so the byte-compiler doesn't warn; savehist defines it for real.
 (defvar savehist-additional-variables)
 
-(with-eval-after-load 'savehist
+(defun wttrin--savehist-register ()
+  "Ensure `wttrin--location-history' is persisted by savehist.
+Run both at load and on `savehist-save-hook', so the registration survives a
+user `setq' of `savehist-additional-variables' (a common config pattern) that
+would otherwise drop the entry before it could be saved."
   (add-to-list 'savehist-additional-variables 'wttrin--location-history))
 
+(with-eval-after-load 'savehist
+  (wttrin--savehist-register)
+  (add-hook 'savehist-save-hook #'wttrin--savehist-register))
+
 (defun wttrin--add-to-location-history (location)
   "Record LOCATION as a recent successful search.
 No-op when LOCATION is nil, empty, or already a default location.  An existing