Adding syntax cheat sheet to pattern

rocketbot/cogs/patterncog.py

 from datetime import datetime
 from typing import Optional
 
-from discord import Guild, Member, Message, utils as discordutils, Permissions, Interaction
-from discord.app_commands import Choice, Group, autocomplete, rename
+from discord import Guild, Member, Message, utils as discordutils, Interaction
+from discord.app_commands import Choice, Group, autocomplete
 from discord.ext.commands import Cog
 
 from config import CONFIG
 		Choice(name='very high (150)', value=150),
 	]
 
+_long_help = \
+"""Patterns are a powerful but complex topic. See <https://git.rixafrix.com/ialbert/python-app-rocketbot/src/branch/main/docs/patterns.md> for full documentation.
+
+### Quick cheat sheet
+
+> `/pattern add` _pattern\\_name_ _action\\_list_ `if` _expression_
+
+- _pattern\\_name_ is a brief name for identifying the pattern later (not shown to user)
+- _action\\_list_ is a comma-delimited list of actions to take on matching messages and is any of:
+   - `ban`
+   - `delete`
+   - `kick`
+   - `modinfo` - logs a message but doesn't tag mods
+   - `modwarn` - tags mods
+   - `reply` "message text"
+- _expression_ determines which messages match, of the form _field_ _op_ _value_.
+   - Fields:
+      - `content.markdown`: string
+      - `content.plain`: string
+      - `author`: user
+      - `author.id`: id
+      - `author.joinage`: timespan
+      - `author.name`: string
+      - `lastmatched`: timespan
+   - Operators: `==`, `!=`, `<`, `>`, `<=`, `>=`, `contains`, `!contains`, `matches`, `!matches`, `containsword`, `!containsword`
+   - Can combine multiple expressions with `!`, `and`, `or`, and parentheses."""
+
 class PatternCog(BaseCog, name='Pattern Matching'):
 	"""
 	Highly flexible cog for performing various actions on messages that match
 			bot,
 			config_prefix='patterns',
 			short_description='Manages message pattern matching.',
-			long_description='Patterns are a powerful but complex topic. See <https://git.rixafrix.com/ialbert/python-app-rocketbot/src/branch/main/docs/patterns.md> for full documentation.'
+			long_description=_long_help
 		)
 		PatternCog.shared = self
 
 		guild_only=True,
 		default_permissions=MOD_PERMISSIONS,
 		extras={
-			'long_description': 'Patterns are a powerful but complex topic. '
-								'See <https://git.rixafrix.com/ialbert/python-app-rocketbot/src/branch/main/docs/patterns.md> for full documentation.'
+			'long_description': _long_help,
 		},
 	)
 
 	@pattern.command(
 		description='Adds or updates a custom pattern.',
 		extras={
-			'long_description': 'Patterns use a simplified expression language. Full '
-								'documentation found here: '
-								'<https://git.rixafrix.com/ialbert/python-app-rocketbot/src/branch/main/docs/patterns.md>',
+			'long_description': _long_help,
 		},
 	)
 	@autocomplete(