patch 8.2.3071: shell options are not set properly for PowerShell

Problem:    Shell options are not set properly for PowerShell.
Solution:   Use better option defaults. (Mike Willams, closes #8459)
diff --git a/src/os_win32.c b/src/os_win32.c
index a966c53..1a005c9 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -2142,7 +2142,8 @@
 	return FALSE;
 
     // Using the name directly when a Unix-shell like 'shell'.
-    if (strstr((char *)gettail(p_sh), "sh") != NULL)
+    if (strstr((char *)gettail(p_sh), "powershell") == NULL
+				&& strstr((char *)gettail(p_sh), "sh") != NULL)
 	noext = TRUE;
 
     if (use_pathext)