Issue #16714: use 'raise' exceptions, don't 'throw'.

Patch by Serhiy Storchaka.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index ea810ec..21a6739 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -349,7 +349,7 @@
 
 #if defined _MSC_VER && _MSC_VER >= 1400
 /* Microsoft CRT in VS2005 and higher will verify that a filehandle is
- * valid and throw an assertion if it isn't.
+ * valid and raise an assertion if it isn't.
  * Normally, an invalid fd is likely to be a C program error and therefore
  * an assertion can be useful, but it does contradict the POSIX standard
  * which for write(2) states: