patch 8.1.1318: code for text changes is in a "misc" file

Problem:    Code for text changes is in a "misc" file.
Solution:   Move the code to change.c.
diff --git a/src/proto.h b/src/proto.h
index 8027232..4d2eded 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -63,6 +63,7 @@
 # endif
 # include "autocmd.pro"
 # include "buffer.pro"
+# include "change.pro"
 # include "charset.pro"
 # ifdef FEAT_CSCOPE
 #  include "if_cscope.pro"