keys: Add key for viewing message sender information.

Binds key 'u' to the 'MSG_SENDER_INFO' command which
shows user information for the sender of a message.

Author: israelsgalaxy

docs/hotkeys.md

@@ -58,6 +58,7 @@
 |Add/remove thumbs-up reaction to the current message|<kbd>+</kbd>|
 |Add/remove star status of the current message|<kbd>ctrl</kbd> + <kbd>s</kbd> / <kbd>*</kbd>|
 |Show/hide message information|<kbd>i</kbd>|
+|Show/hide message sender information|<kbd>u</kbd>|
 |Show/hide edit history (from message information)|<kbd>e</kbd>|
 |View current message in browser (from message information)|<kbd>v</kbd>|
 |Show/hide full rendered message (from message information)|<kbd>f</kbd>|

zulipterminal/config/keys.py

@@ -264,6 +264,11 @@ class KeyBinding(TypedDict):
         'help_text': 'Show/hide message information',
         'key_category': 'msg_actions',
     },
+    'MSG_SENDER_INFO': {
+        'keys': ['u'],
+        'help_text': 'Show/hide message sender information',
+        'key_category': 'msg_actions',
+    },
     'EDIT_HISTORY': {
         'keys': ['e'],
         'help_text': 'Show/hide edit history (from message information)',