[balsa/wip/gtk4: 345/351] filter-run: Document the private nature

[Peter Bloomfield <peterb src gnome org>]

commit d995bcde2de1e1efb1e9e268f9be7536f35a7fe1
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Mon May 7 09:01:58 2018 -0400

    filter-run: Document the private nature
    
    of FilterRunDialog.

 src/filter-run.h |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/filter-run.h b/src/filter-run.h
index 162798f..b82a409 100644
--- a/src/filter-run.h
+++ b/src/filter-run.h
@@ -41,6 +41,9 @@ G_BEGIN_DECLS
 
 
 struct _BalsaFilterRunDialog {
+    /* This object is shared by filter-run-dialog.c and
+     * filter-run-callbacks.c, so we keep it public, but this file
+     * should not be included in other files. */
     GtkDialog parent;
 
     /* GUI members */