Fix a regression that caused using the `title` command in session files to stop working

Fixes #3676

docs/changelog.rst

@@ -73,6 +73,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 
 - Tab bar: Use a lower contrast color for tab separators (:pull:`3666`)
 
+- Fix a regression that caused using the ``title`` command in session files
+  to stop working (:iss:`3676`)
+
 
 0.20.3 [2021-05-06]
 ----------------------

docs/index.rst

@@ -221,8 +221,7 @@ For example:
     # vim in it
     launch --env FOO=BAR vim
     # Set the title for the next window
-    title Chat with x
-    launch irssi --profile x
+    launch --title "Chat with x" irssi --profile x
 
     # Create a new tab (the part after new_tab is the optional tab
     # name which will be displayed in the tab bar, if omitted, the

kitty/session.py

@@ -68,6 +68,8 @@ class Session:
         if self.default_watchers:
             spec.opts.watcher = list(spec.opts.watcher) + self.default_watchers
         t = self.tabs[-1]
+        if t.next_title and not spec.opts.window_title:
+            spec.opts.window_title = t.next_title
         spec.opts.cwd = spec.opts.cwd or t.cwd
         t.windows.append(spec)
         t.next_title = None