keys: Improve descriptions of hotkeys that switch narrows.

Replace "Narrow to":
- Use "View" instead of "Narrow to"
- Use "View all" for those corresponding to narrow buttons
- Use "Switch message view" for the compose box message recipient

Rephrasing help texts:
- Use "zoom in/out" to simplify and shorten the longest description,
  while also being clear on the choice of key being 'z'
- "compose box message recipient" -> "compose box target" reduces length
  and user-friendliness, while retaining clarity

Hotkeys document regenerated.

docs/hotkeys.md

@@ -30,14 +30,14 @@
 ## Switching Messages View
 |Command|Key Combination|
 | :--- | :---: |
-|Narrow to the stream of the current message|<kbd>s</kbd>|
-|Narrow to the topic of the current message|<kbd>S</kbd>|
-|Narrow to a topic/direct-chat, or stream/all-direct-messages|<kbd>z</kbd>|
-|Narrow to compose box message recipient|<kbd>Meta</kbd> + <kbd>.</kbd>|
-|Narrow to all messages|<kbd>a</kbd> / <kbd>Esc</kbd>|
-|Narrow to all direct messages|<kbd>P</kbd>|
-|Narrow to all starred messages|<kbd>f</kbd>|
-|Narrow to messages in which you're mentioned|<kbd>#</kbd>|
+|View the stream of the current message|<kbd>s</kbd>|
+|View the topic of the current message|<kbd>S</kbd>|
+|Zoom in/out the message's conversation context|<kbd>z</kbd>|
+|Switch message view to the compose box target|<kbd>Meta</kbd> + <kbd>.</kbd>|
+|View all messages|<kbd>a</kbd> / <kbd>Esc</kbd>|
+|View all direct messages|<kbd>P</kbd>|
+|View all starred messages|<kbd>f</kbd>|
+|View all messages in which you're mentioned|<kbd>#</kbd>|
 |Next unread topic|<kbd>n</kbd>|
 |Next unread direct message|<kbd>p</kbd>|
 

zulipterminal/config/keys.py

@@ -169,23 +169,23 @@ class KeyBinding(TypedDict):
     },
     'STREAM_NARROW': {
         'keys': ['s'],
-        'help_text': 'Narrow to the stream of the current message',
+        'help_text': 'View the stream of the current message',
         'key_category': 'narrowing',
     },
     'TOPIC_NARROW': {
         'keys': ['S'],
-        'help_text': 'Narrow to the topic of the current message',
+        'help_text': 'View the topic of the current message',
         'key_category': 'narrowing',
     },
     'TOGGLE_NARROW': {
         'keys': ['z'],
         'help_text':
-            'Narrow to a topic/direct-chat, or stream/all-direct-messages',
+            "Zoom in/out the message's conversation context",
         'key_category': 'narrowing',
     },
     'NARROW_MESSAGE_RECIPIENT': {
         'keys': ['meta .'],
-        'help_text': 'Narrow to compose box message recipient',
+        'help_text': 'Switch message view to the compose box target',
         'key_category': 'narrowing',
     },
     'EXIT_COMPOSE': {
@@ -205,22 +205,22 @@ class KeyBinding(TypedDict):
     },
     'ALL_MESSAGES': {
         'keys': ['a', 'esc'],
-        'help_text': 'Narrow to all messages',
+        'help_text': 'View all messages',
         'key_category': 'narrowing',
     },
     'ALL_PM': {
         'keys': ['P'],
-        'help_text': 'Narrow to all direct messages',
+        'help_text': 'View all direct messages',
         'key_category': 'narrowing',
     },
     'ALL_STARRED': {
         'keys': ['f'],
-        'help_text': 'Narrow to all starred messages',
+        'help_text': 'View all starred messages',
         'key_category': 'narrowing',
     },
     'ALL_MENTIONS': {
         'keys': ['#'],
-        'help_text': "Narrow to messages in which you're mentioned",
+        'help_text': "View all messages in which you're mentioned",
         'key_category': 'narrowing',
     },
     'NEXT_UNREAD_TOPIC': {