patch 8.1.2058: function for ex command is named inconsistently

Problem:    Function for ex command is named inconsistently.
Solution:   Rename do_marks() to ex_marks().
diff --git a/src/version.c b/src/version.c
index 3ed4c80..1bfe75c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2058,
+/**/
     2057,
 /**/
     2056,