patch 8.1.1727: code for viminfo support is spread out

Problem:    Code for viminfo support is spread out.
Solution:   Move to code to viminfo.c. (Yegappan Lakshmanan, closes #4686)
diff --git a/src/proto/viminfo.pro b/src/proto/viminfo.pro
new file mode 100644
index 0000000..4d7b46e
--- /dev/null
+++ b/src/proto/viminfo.pro
@@ -0,0 +1,10 @@
+/* viminfo.c */
+int viminfo_error(char *errnum, char *message, char_u *line);
+int read_viminfo(char_u *file, int flags);
+void write_viminfo(char_u *file, int forceit);
+int viminfo_readline(vir_T *virp);
+char_u *viminfo_readstring(vir_T *virp, int off, int convert);
+void viminfo_writestring(FILE *fd, char_u *p);
+int barline_writestring(FILE *fd, char_u *s, int remaining_start);
+void ex_viminfo(exarg_T *eap);
+/* vim: set ft=c : */