keys: Add TOPIC_INFO shortcut using 'i' key to show/hide topic settings.

Co-authored-by: Shivam Deotarse <srdeotarse@gmail.com>

Author: rsashank

docs/hotkeys.md

@@ -75,6 +75,11 @@
 |Show/hide user information|<kbd>i</kbd>|
 |Narrow to direct messages with user|<kbd>Enter</kbd>|
 
+## Topic actions
+|Command|Key Combination|
+| :--- | :---: |
+|Show/hide topic information & modify settings|<kbd>i</kbd>|
+
 ## Begin composing a message
 |Command|Key Combination|
 | :--- | :---: |

zulipterminal/config/keys.py

@@ -312,6 +312,11 @@ class KeyBinding(TypedDict):
         'help_text': 'Show/hide stream information & modify settings',
         'key_category': 'stream_list',
     },
+    'TOPIC_INFO': {
+        'keys': ['i'],
+        'help_text': 'Show/hide topic information & modify settings',
+        'key_category': 'topic_actions',
+    },
     'STREAM_MEMBERS': {
         'keys': ['m'],
         'help_text': 'Show/hide stream members',
@@ -467,6 +472,7 @@ class KeyBinding(TypedDict):
     "msg_actions": "Message actions",
     "stream_list": "Stream list actions",
     "user_list": "User list actions",
+    "topic_actions": "Topic actions",
     "open_compose": "Begin composing a message",
     "compose_box": "Writing a message",
     "editor_navigation": "Editor: Navigation",