Logic in Source Command's Help Command Check
## Description
<!-- Describe the bug you've found -->
Its impossible to get the source for the HelpChannel cog.

## Steps to Reproduce
<!-- Detail the exact list of steps to be able to encounter the bug -->
`!src HelpChannel`
Due to the logic of the command, all that needs to be said is `!src help` followed by anything.

## Expected Behaviour
<!-- Outline what you expect to occur, include screenshots if relevant -->
Source link to the HelpChannel cog is shown.

## Actual Behaviour
<!-- Outline what occurs instead of the expected behavior, include screenshots if relevant -->
Help command source link is shown.

## Known Impacted Platforms
<!-- Replace [ ] with [x] to mark items -->

- [x] Web
- [x] Desktop
- [x] Android App
- [x] iOS App

## Possible Solutions
<!-- Detail any solutions you might have in mind to be able to resolve the bug -->
These lines are the probable cause.
https://github.com/python-discord/bot/blob/51af1369e0d9c2ad185f0c0920b599b7187ed077/bot/exts/info/source.py#L19-L20
After looking at sir-lancebot, it might even be possible to remove these two lines altogether.
## Would you like to implement a fix?

***Note: For high-priority or critical bugs, fixes may be implemented by staff.***
<!-- Replace [ ] with [x] with your choice -->

- [ ] I'd like to implement the bug fix
- [x] Anyone can implement the bug fix

diff --git a/bot/exts/info/source.py b/bot/exts/info/source.py
index 78a6f68a..ef07c77a 100644
--- a/bot/exts/info/source.py
+++ b/bot/exts/info/source.py
@@ -14,9 +14,10 @@ SourceType = Union[commands.HelpCommand, commands.Command, commands.Cog, str, co
 class SourceConverter(commands.Converter):
     """Convert an argument into a help command, tag, command, or cog."""
 
-    async def convert(self, ctx: commands.Context, argument: str) -> SourceType:
+    @staticmethod
+    async def convert(ctx: commands.Context, argument: str) -> SourceType:
         """Convert argument into source object."""
-        if argument.lower().startswith("help"):
+        if argument.lower() == "help":
             return ctx.bot.help_command
 
         cog = ctx.bot.get_cog(argument)
['bot/exts/info/source.py']