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

Hotkeys updated.

Author: srdeotarse

docs/hotkeys.md

@@ -13,6 +13,7 @@
 |Redraw screen|<kbd>ctrl</kbd> + <kbd>l</kbd>|
 |Quit|<kbd>ctrl</kbd> + <kbd>c</kbd>|
 |View user information (From Users list)|<kbd>i</kbd>|
+|Show/hide topic information & modify settings|<kbd>i</kbd>|
 
 ## Navigation
 |Command|Key Combination|

zulipterminal/config/keys.py

@@ -311,6 +311,11 @@ class KeyBinding(TypedDict):
         'help_text': 'View user information (From Users list)',
         'key_category': 'general',
     }),
+    ('TOPIC_INFO', {
+        'keys': ['i'],
+        'help_text': 'Show/hide topic information & modify settings',
+        'key_category': 'general',
+    }),
     ('BEGINNING_OF_LINE', {
         'keys': ['ctrl a'],
         'help_text': 'Jump to the beginning of line',