Clarify documentation of the scan endpoint (#44)

Signed-off-by: Kim Brose <2803622+HarHarLinks@users.noreply.github.com>

I think there was a copy-paste error here, otherwise this API is missing
a way to scan the actual media which I find hard to believe.

Signed-off-by: Kim Brose <2803622+HarHarLinks@users.noreply.github.com>

docs/api.md

@@ -57,7 +57,7 @@ unsuccessful, an error is sent with the reason `MCS_MEDIA_NOT_CLEAN`.
 
 ### `GET /_matrix/media_proxy/unstable/scan/{serverName}/{mediaId}`
 
-Downloads a thumbnail of the media at `mxc://{serverName}/{mediaId}`, scans it and
+Downloads the media at `mxc://{serverName}/{mediaId}`, scans it and
 responds with the result of the scan.
 
 Response format:
@@ -178,4 +178,4 @@ Example (generated using the body and public key from the previous examples):
         "ephemeral": "fk2xOTmttnFDTAORxVQTtIlbsu7O01Oe52+umaOjIiE"
     }
 }
-```
+```