docs: Update GH_NOTIFY_FZF_OPTS description and usage

gh-notify

@@ -534,8 +534,10 @@ select_notif() {
     # a failed 'print_notifs' call, but does not display the message.
 
     # See the man page (man fzf) for an explanation of the arguments.
+
     output=$(
-        SHELL="$(which bash)" command fzf \
+        # shellcheck disable=SC2086
+        SHELL="$(which bash)" command fzf ${GH_NOTIFY_FZF_OPTS:-} \
             --ansi \
             --bind "${GH_NOTIFY_RESIZE_PREVIEW_KEY}:change-preview-window(75%:nohidden|75%:down:nohidden:border-top|nohidden)" \
             --bind "change:first" \

readme.md

@@ -101,6 +101,17 @@ export FZF_DEFAULT_OPTS="
 --bind 'ctrl-w:preview-half-page-up,ctrl-s:preview-half-page-down'"
 ```
 
+#### GH_NOTIFY_FZF_OPTS
+This environment variable lets you specify additional options and key bindings to customize the
+search and display of notifications. Unlike `FZF_DEFAULT_OPTS`, `GH_NOTIFY_FZF_OPTS` specifically
+applies to the `gh notify` extension.
+
+```sh
+# --exact: Enables exact matching instead of fuzzy matching.
+GH_NOTIFY_FZF_OPTS="--exact" gh notify
+```
+
+#### Modifying Keybindings
 You can also customize the keybindings created by this extension to avoid conflicts with
 the ones defined by `fzf`. For example, change `ctrl-p` to `ctrl-u`: