Use language=grammar for modifiers in redeclaration and improve language

Addressing comment by Hans:
- modelica#2916 (comment)

chapters/inheritance.tex

@@ -577,7 +577,7 @@ \section{Redeclaration}\label{redeclaration}
 A \lstinline!redeclare! construct as an element replaces the declaration of a local class or component with another declaration.
 Both \lstinline!redeclare! constructs work in the same way.
 The \lstinline!redeclare! construct as an element requires that the element is inherited, and cannot be combined with a modifier of the same element in the extends-clause.
-For modifiers the redeclare of classes uses a special short class definition construct; that is a subset of normal class definitions and semantically behave as the corresponding class-definition.
+For modifiers, the redeclare of classes uses a special \lstinline[language=grammar]!short-class-definition! construct, which is a subset of normal class definitions and semantically behaves as the corresponding \lstinline[language=grammar]!class-definition!.
 
 A modifier with the keyword \lstinline!replaceable!\indexinline{replaceable} is automatically seen as being a \lstinline!redeclare!.