Add small note to perforce p4.port docs (#576)

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Author: pjlast

docs/admin/repo/perforce.mdx

@@ -203,10 +203,11 @@ When file-level permissions are enabled, Sourcegraph will read the Perforce prot
 	// The ticket value for the user (P4PASSWD). You can get this by running `p4 login -p` or `p4 login -pa`. It should look like `6211C5E719EDE6925855039E8F5CC3D2`.
 	"p4.passwd": null,
 
-	// The Perforce Server address to be used for p4 CLI (P4PORT).
+	// The Perforce Server address to be used for p4 CLI (P4PORT). It's recommended to specify the protocol prefix (e.g. tcp: or ssl:) as part of the address.
 	"p4.port": null,
 	// Other example values:
 	// - "ssl:111.222.333.444:1666"
+	// - "tcp:111.222.333.444:1666"
 
 	// The user to be authenticated for p4 CLI (P4USER).
 	"p4.user": null,