ax(mining): replace prose comment on StopMiner with usage example

AX Principle 2 — comments show HOW with real values, not what the
signature already says. Prose restating the method signature deleted;
concrete call examples with realistic miner names substituted.

Co-Authored-By: Charon <charon@lethean.io>

pkg/mining/manager.go

@@ -405,9 +405,8 @@ func (m *Manager) updateMinerConfig(minerType string, autostart bool, config *Co
 	})
 }
 
-// StopMiner stops a running miner and removes it from the manager.
-// If the miner is already stopped, it will still be removed from the manager.
-// The context can be used to cancel the operation.
+// manager.StopMiner(ctx, "xmrig/monero")
+// manager.StopMiner(ctx, "ttminer/rtx4090") // still removes if already stopped
 func (m *Manager) StopMiner(ctx context.Context, name string) error {
 	// Check for cancellation before acquiring lock
 	select {