[std] Use \keyword for access specifiers.

Author: jensmaurer

source/classes.tex

@@ -4112,7 +4112,7 @@
 Members of a class defined with the keyword
 \keyword{class}
 are
-\tcode{private}
+\keyword{private}
 by default.
 Members of a class defined with the keywords
 \keyword{struct} or \keyword{union}
@@ -4352,19 +4352,19 @@
 
 \pnum
 If a class is declared to be a base class\iref{class.derived} for another class using the
-\tcode{public}
+\keyword{public}
 access specifier, the
 public members of the base class are accessible as
 public members of the derived class and
 protected members of the base class are accessible as
 protected members of the derived class.
 If a class is declared to be a base class for another class using the
-\tcode{protected}
+\keyword{protected}
 access specifier, the
 public and protected members of the base class are accessible as
 protected members of the derived class.
 If a class is declared to be a base class for another class using the
-\tcode{private}
+\keyword{private}
 access specifier, the
 public and protected
 members of the base class are accessible as private
@@ -4380,12 +4380,12 @@
 In the absence of an
 \grammarterm{access-specifier}
 for a base class,
-\tcode{public}
+\keyword{public}
 is assumed when the derived class is
 defined with the \grammarterm{class-key}
 \keyword{struct}
 and
-\tcode{private}
+\keyword{private}
 is assumed when the class is
 defined with the \grammarterm{class-key}
 \keyword{class}.