Document slash command and query filter in docs for chat and search

docs/chat.md

@@ -27,11 +27,21 @@ Online chat requires internet to use ChatGPT but is faster, higher quality and l
 
 
 ### Use
-1. Open [/chat](http://localhost:42110/chat)
-2. Type your queries and see Khoj respond using your notes as reference
+1. Open Khoj Chat
+    - **On Web**: Open [/chat](http://localhost:42110/chat) in your web browser
+    - **On Obsidian**: Search for *Khoj: Chat* in the [Command Palette](https://help.obsidian.md/Plugins/Command+palette)
+    - **On Emacs**: Run `M-x khoj <user-query>`
+2. Enter your queries to chat with Khoj. Use [slash commands](#commands) and [query filters](./advanced.md#query-filters) to change what Khoj uses to respond
 
 ![](./assets/khoj_chat_on_web.png ':size=400px')
 
 #### Details
 1. Your query is used to retrieve the most relevant notes, if any, using Khoj search
 2. These notes, the last few messages and associated metadata is passed to the enabled chat model along with your query to generate a response
+
+#### Commands
+Slash commands allows you to change what Khoj uses to respond to your query
+- **/notes**: Limit chat to only respond using your notes, not just Khoj's general world knowledge as reference
+- **/general**: Limit chat to only respond using Khoj's general world knowledge, not using your notes as reference
+- **/default**: Allow chat to respond using your notes or it's general knowledge as reference. It's the default behavior when no slash command is used
+- **/help**: Use /help to get all available commands and general information about Khoj