fix bot lifecycle and docs

tgapi/errors.go

@@ -2,7 +2,14 @@ package tgapi
 
 import "errors"
 
+// ErrRateLimit reports that a request exceeded the configured rate limiter.
 var ErrRateLimit = errors.New("rate limit exceeded")
+
+// ErrPoolUnexpected reports an unexpected result type returned from the worker pool.
 var ErrPoolUnexpected = errors.New("unexpected response from pool")
+
+// ErrPoolQueueFull reports that the internal request queue is full.
 var ErrPoolQueueFull = errors.New("worker pool queue full")
+
+// ErrPoolStopped reports that a request was submitted after the worker pool stopped.
 var ErrPoolStopped = errors.New("worker pool stopped")