Fix CSS view prompt, update display mode options.

libmproxy/console/contentview.py

@@ -335,7 +335,7 @@ class ViewJavaScript:
 
 class ViewCSS:
     name = "CSS"
-    prompt = ("CSS", "c")
+    prompt = ("css", "c")
     content_types = [
         "text/css"
     ]

libmproxy/console/help.py

@@ -61,6 +61,10 @@ class HelpView(urwid.ListBox):
                     common.highlight_key("json", "s") +
                     [("text", ": JSON")]
                 ),
+                (None,
+                    common.highlight_key("css", "c") +
+                    [("text", ": CSS")]
+                ),
                 (None,
                     common.highlight_key("urlencoded", "u") +
                     [("text", ": URL-encoded data")]