docs: the fzf example copies and closes on ctrl-y, copies and stays on alt-y

docs/links.md

@@ -157,8 +157,10 @@ instead, showing the names and acting on the links:
 
 ```sh
 lazysecrets list | fzf --ansi --with-nth='2..-3' --accept-nth=-1 \
+  --header 'enter: link · ctrl-o: open · ctrl-y: copy value · alt-y: copy, stay' \
   --bind 'ctrl-o:become(lazysecrets open --action go --account {-2} {-1})' \
-  --bind 'ctrl-y:execute-silent(lazysecrets get --account {-2} {-1} | pbcopy)'
+  --bind 'ctrl-y:become(lazysecrets get --account {-2} {-1} | pbcopy)' \
+  --bind 'alt-y:execute-silent(lazysecrets get --account {-2} {-1} | pbcopy)+change-header(Copied the value of {2..-3})'
 ```
 
 `--with-nth='2..-3'` shows and searches only the names; `{-1}` and
@@ -167,7 +169,8 @@ one word, so this works without `--delimiter`. To filter by kind
 yourself: `awk -F'\t' '$1 == "secret"'`.
 
 `enter` prints the link (`lazysecrets get $(…)`), `ctrl-o` opens it in
-lazysecrets and `ctrl-y` copies the value (`pbcopy` on macOS; `wl-copy` or
+lazysecrets, `ctrl-y` copies the value and closes fzf, and `alt-y` copies
+it and stays, saying so in the header (`pbcopy` on macOS; `wl-copy` or
 `xclip` on Linux). A value copied this way isn't cleared from the
 clipboard after `values.clipboardClear`, as one copied in lazysecrets is.