docs: Fix broken links (#16943)

This PR fixes some broken links in the docs.

All internal links within the docs should be relative links so that
mdBook can resolve them to another page and generate the appropriate
URL.

Release Notes:

- N/A

docs/src/assistant/commands.md

@@ -9,7 +9,7 @@ Slash commands enhance the assistant's capabilities. Begin by typing a `/` at th
 - `/fetch`: Fetches the content of a webpage and inserts it into the context
 - `/file`: Inserts a single file or a directory of files into the context
 - `/now`: Inserts the current date and time into the context
-- `/prompt`: Adds a custom-configured prompt to the context ([see Prompt Library](/docs/assistant/prompting#prompt-library))
+- `/prompt`: Adds a custom-configured prompt to the context ([see Prompt Library](./prompting#prompt-library))
 - `/symbols`: Inserts the current tab's active symbols into the context
 - `/tab`: Inserts the content of the active tab or all open tabs into the context
 - `/terminal`: Inserts a select number of lines of output from the terminal
@@ -25,7 +25,7 @@ Slash commands enhance the assistant's capabilities. Begin by typing a `/` at th
 
 ## `/default`
 
-Read more about `/default` in the [Prompting: Editing the Default Prompt](/assistant/prompting.md#default-prompt) section.
+Read more about `/default` in the [Prompting: Editing the Default Prompt](./prompting.md#default-prompt) section.
 
 Usage: `/default`