Documentation update regarding right font usage in architecture chapter

Small update, setting program names in right font

doc/arch.doc

@@ -190,12 +190,12 @@ could extract information from the XML output. Possible tools could be:
 Since doxygen uses a lot of \c flex code it is important to understand
 how \c flex works (for this one should read the \c man page) 
 and to understand what it is doing when \c flex is parsing some input. 
-Fortunately, when flex is used with the `-d` option it outputs what rules
+Fortunately, when \c flex is used with the `-d` option it outputs what rules
 matched. This makes it quite easy to follow what is going on for a 
 particular input fragment. 
 
-To make it easier to toggle debug information for a given flex file I
-wrote the following perl script, which automatically adds or removes `-d`
+To make it easier to toggle debug information for a given \c flex file I
+wrote the following \c perl script, which automatically adds or removes `-d`
 from the correct line in the \c Makefile:
 
 \verbatim
@@ -240,7 +240,7 @@ $now = time;
 utime $now, $now, $file;
 \endverbatim
 Another way to get rules matching / debugging information
-from the \c flex code is setting LEX_FLAGS with \c make (`make LEX_FLAGS=-d`).
+from the \c flex code is setting \c LEX_FLAGS with \c make (`make LEX_FLAGS=-d`).
 
 Note that by running doxygen with `-d lex` you get information about which 
 `flex codefile` is used.