[gtkmm-documentation/wip/dboles/formatting-3: 5/10] Improve gtkmm 3 intro re # of changes from gtkmm 2

[Daniel Boles <dboles src gnome org>]

commit d330858fb99b21b7ebd8059a45cf5579c81ee957
Author: Daniel Boles <dboles src gmail com>
Date:   Mon Jan 15 21:16:21 2018 +0000

    Improve gtkmm 3 intro re # of changes from gtkmm 2
    
    I wasn’t around, but I think it’s a bit of an understatement to say that
    “gtkmm 3 has no major fundamental differences to gtkmm 2”… A lot of the
    changes might, even in isolation, be viewed as fundamental by GTK+ 2
    users making the change, depending on how they were using gtkmm 2.

 docs/tutorial/C/index-in.docbook |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/docs/tutorial/C/index-in.docbook b/docs/tutorial/C/index-in.docbook
index e40af67..c5f3fab 100644
--- a/docs/tutorial/C/index-in.docbook
+++ b/docs/tutorial/C/index-in.docbook
@@ -705,8 +705,8 @@ then finish.
 <para><application>gtkmm-3.0</application> is a new version of the &gtkmm; API
 that installs in parallel with the older <application>gtkmm-2.4</application>
 API. The last version of the <application>gtkmm-2.4</application> API was 2.24.
-&gtkmm; 3 has no major fundamental differences to &gtkmm; 2 but does make
-several small changes that were not possible while maintaining binary
+Like GTK+, &gtkmm; made various changes in version 3, of the kind that could not
+be made in version 2 of either library because of the need to maintain API/ABI
 compatibility. If you never used the <application>gtkmm-2.4</application> API
 then you can safely ignore this chapter.</para>