Issue #12423: Fix os.abort() documentation

The Python signal handler for SIGABRT is not called on os.abort() (only if the
signal is raised manually or sent by another process). Patch by Kamil Kisiel.
diff --git a/Doc/ACKS.txt b/Doc/ACKS.txt
index 7f67d36..1ad18f1 100644
--- a/Doc/ACKS.txt
+++ b/Doc/ACKS.txt
@@ -105,6 +105,7 @@
    * Robert Kern
    * Jim Kerr
    * Jan Kim
+   * Kamil Kisiel
    * Greg Kochanski
    * Guido Kollerie
    * Peter A. Koren
@@ -142,7 +143,7 @@
    * Ross Moore
    * Sjoerd Mullender
    * Dale Nagata
-   * Michal Nowikowski 
+   * Michal Nowikowski
    * Ng Pheng Siong
    * Koray Oner
    * Tomas Oppelstrup