patch 8.2.0996: using "aucmdwin" in win_gettype() is not ideal

Problem:    Using "aucmdwin" in win_gettype() is not ideal.
Solution:   Rename to "autocmd".
diff --git a/src/evalwindow.c b/src/evalwindow.c
index 585ff72..0b3052c 100644
--- a/src/evalwindow.c
+++ b/src/evalwindow.c
@@ -859,7 +859,7 @@
 	}
     }
     if (wp == aucmd_win)
-	rettv->vval.v_string = vim_strsave((char_u *)"aucmdwin");
+	rettv->vval.v_string = vim_strsave((char_u *)"autocmd");
 #if defined(FEAT_QUICKFIX)
     else if (wp->w_p_pvw)
 	rettv->vval.v_string = vim_strsave((char_u *)"preview");