Fix inactive branches being marked with ^
Patch from Simon Williams.
    
        | author | 
        Steve Losh <steve@stevelosh.com> | 
    
    
        | date | 
        Sun, 19 Jul 2020 11:12:21 -0400 | 
    
    
    
        | parents | 
        9f0b70dfcf52 
 | 
    
    
        | children | 
        cc789a5baf4a
 | 
    
    
        | branches/tags | 
        (none) | 
    
    
        | files | 
        prompt.py  | 
    
Changes
    
--- a/prompt.py	Mon Dec 23 15:00:33 2019 -0500
+++ b/prompt.py	Sun Jul 19 11:12:21 2020 -0400
@@ -341,7 +341,7 @@
                 tip = head
                 break
 
-        return _with_groups(m.groups(), '^') if current_rev.children() else ''
+        return _with_groups(m.groups(), '^') if repo[tip].node() != current_rev.node() else ''
 
     if opts.get("angle_brackets"):
         tag_start = r'\<([^><]*?\<)?'