Fixed typo reported by Vladimir Marangozov <Vladimir.Marangozov@imag.fr>.

Doc/api.tex

@@ -2510,7 +2510,7 @@ The Python interpreter is not fully thread safe.  In order to support
 multi-threaded Python programs, there's a global lock that must be
 held by the current thread before it can safely access Python objects.
 Without the lock, even the simplest operations could cause problems in
-a multi-threaded proram: for example, when two threads simultaneously
+a multi-threaded program: for example, when two threads simultaneously
 increment the reference count of the same object, the reference count
 could end up being incremented only once instead of twice.
 

Doc/api/api.tex

@@ -2510,7 +2510,7 @@ The Python interpreter is not fully thread safe.  In order to support
 multi-threaded Python programs, there's a global lock that must be
 held by the current thread before it can safely access Python objects.
 Without the lock, even the simplest operations could cause problems in
-a multi-threaded proram: for example, when two threads simultaneously
+a multi-threaded program: for example, when two threads simultaneously
 increment the reference count of the same object, the reference count
 could end up being incremented only once instead of twice.