[gtkmm-documentation/wip/dboles/formatting-3: 5/8] Replace uses of "derivation" with "inheritance"

[Daniel Boles <dboles src gnome org>]

commit 561d626a95d4fc9b5cfebbaf25d9f498d3969889
Author: Daniel Boles <dboles src gmail com>
Date:   Mon Jan 15 19:15:35 2018 +0000

    Replace uses of "derivation" with "inheritance"
    
    One of these terms is a lot more popular than the other!
    
    I also unilaterally take issue with the statement that inheritance is
    "essential" for "Object Orientated [sic]" programming: while a main
    technique, it is not essential at all, and in fact, nowadays the mantra
    is to prefer composition or other alternatives, wherever inheritance is
    not strictly required. Granted, gtkmm/GTK+ et al. make heavy use of
    inheritance, but I wouldn't call it "essential" in C++ or OOP generally.
    There are many more, and often much more interesting, other paradigms.
    
    Finally, I update one GTK+ use to have <application> tags like all the
    surrounding ones. However, we are by no means consistent about this. We
    should probably try to be. My current thinking is that those tags are
    only really useful if the name needs help to stand out from the normal
    text around it, which only really happens if it's totally lower-case.

 docs/tutorial/C/index-in.docbook |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/docs/tutorial/C/index-in.docbook b/docs/tutorial/C/index-in.docbook
index 6d34ea4..515a3c5 100644
--- a/docs/tutorial/C/index-in.docbook
+++ b/docs/tutorial/C/index-in.docbook
@@ -149,9 +149,14 @@ generally went by the name &gtkmm;, and that's what we stuck with.</para>
 
 <sect2 id="why-use-gtkmm">
 <title>Why use &gtkmm; instead of GTK+?</title>
-<para>&gtkmm; allows you to write code using normal C++ techniques such as encapsulation, derivation, and 
polymorphism. As a C++ programmer you probably already realise that this leads to clearer and better 
organized code.</para>
+<para>&gtkmm; allows you to write code using normal C++ techniques such as
+encapsulation, inheritance, and polymorphism. As a C++ programmer, you probably
+already realise that this leads to clearer and better organized code.</para>
 <para>&gtkmm; is more type-safe, so the compiler can detect errors that would only be detected at run time 
when using C. This use of specific types also makes the API clearer because you can see what types should be 
used just by looking at a method's declaration.</para>
-<para>Inheritance can be used to derive new widgets. The derivation of new widgets in GTK+ C code is so 
complicated and error prone that almost no C coders do it. As a C++ developer you know that derivation is an 
essential Object Orientated technique.</para>
+<para>Inheritance can be used to derive new widgets. Creating new derived widget
+classes in GTK+ C code is so complicated and error prone that almost no C coders
+do it. As a C++ developer you know that inheritance is one of the main
+techniques that object-oriented programming provides to ease design.</para>
 <para>Member instances can be used, simplifying memory management. All GTK+ C widgets are dealt with by use 
of pointers. As a C++ coder you know that pointers should be avoided where possible.</para>
 <para>&gtkmm; involves less code compared to GTK+, which uses prefixed function names and lots of cast 
macros.</para>
 </sect2>
@@ -8969,10 +8974,10 @@ Of course, a normal "clicked" signal handler would have no arguments.
 <function>sigc::bind()</function> is not commonly used, but you might find it
 helpful sometimes. If you are familiar with <application>GTK+</application>
 programming then you have probably noticed that this is similar to the extra
-<parameter>gpointer data</parameter> arguments which all GTK+ callbacks have. This
+<parameter>gpointer data</parameter> arguments which all <application>GTK+</application> callbacks have. This
 is generally overused in <application>GTK+</application> to pass information
-that should be stored as member data in a derived widget, but widget derivation
-is very difficult in C. We have far less need of this hack in &gtkmm;.
+that should be stored as member data in a derived widget, but creating derived
+widget classes is very difficult in C. We have far less need of this hack in &gtkmm;.
 </para>
 </sect1>