backoff/tries.go: fix typo: missing 'o' : anther --> another

WithMaxTries creates a wrapper around another BackOff, which will
return Stop if NextBackOff() has been called too many times since
the last time Reset() was called

Note: Implementation is not thread-safe.

Signed-off-by: Michael Ira Krufky <mkrufky@gmail.com>

tries.go

@@ -3,7 +3,7 @@ package backoff
 import "time"
 
 /*
-WithMaxTries creates a wrapper around anther BackOff, which will
+WithMaxTries creates a wrapper around another BackOff, which will
 return Stop if NextBackOff() has been called too many times since
 the last time Reset() was called