Fix typo in side-inputs (apache#30817)

learning/tour-of-beam/learning-content/core-transforms/side-inputs/description.md

@@ -113,7 +113,7 @@ func init() {
 ```
 # Side inputs are available as extra arguments in the DoFn's process method or Map / FlatMap's callable.
 # Optional, positional, and keyword arguments are all supported. Deferred arguments are unwrapped into their
-# actual values. For example, using pvalue.AsIteor(pcoll) at pipeline construction time results in an iterable
+# actual values. For example, using pvalue.AsIter(pcoll) at pipeline construction time results in an iterable
 # of the actual elements of pcoll being passed into each process invocation. In this example, side inputs are
 # passed to a FlatMap transform as extra arguments and consumed by filter_using_length.
 words = ...
@@ -289,4 +289,4 @@ def join_fn(persons, cities_to_time):
         'name': person['name'],
         'city
 ```
-{{end}}
+{{end}}