feat: add wttrin-hide-follow-line to hide the wttr.in follow line

I added a boolean defcustom, wttrin-hide-follow-line (default nil), that suppresses the "Follow @igor_chubin for wttr.in updates" line in the weather buffer. When it's on, wttrin--build-url adds the wttr.in F flag to the request, so the service omits the line server-side. That stays correct across languages, where a local regex on the English text would miss translated responses.

The helper wttrin--effective-display-options folds F into wttrin-display-options when hiding and F isn't already there, so the toggle and the options string compose without duplicating the flag. The default is off to keep current behavior on upgrade and to leave the upstream author's follow request in place unless the user opts out.

It affects the weather buffer only. The mode-line uses its own compact format with no follow line.

1 files changed, 8 insertions, 0 deletions

diff --git a/README.org b/README.org
index 56b0cb9..ce4b420 100644
--- a/README.org
+++ b/README.org
@@ -218,6 +218,14 @@ wttr.in supports a handful of single-character flags that change what the report
 
 The full list of flags is at https://wttr.in/:help. Skip =A= and =T= — wttrin manages ANSI output internally so the colored glyphs render correctly.
 
+If the one flag you want is the "Follow" line off, there's a dedicated toggle so you don't have to remember =F=:
+
+#+begin_src emacs-lisp
+  (setq wttrin-hide-follow-line t)  ;; hide "Follow @igor_chubin for wttr.in updates"
+#+end_src
+
+It composes with =wttrin-display-options= (setting either one hides the line) and affects the weather buffer only, not the mode-line.
+
 *** Cache Settings
 Wttrin caches weather data and refreshes it in the background. By default it refreshes every hour and keeps up to 50 entries. You can adjust both: