Add module part to customize documentation

- adding missing module part
- small corrections about available items
- small layout issues

Author: albert-github

doc/customize.dox

@@ -301,6 +301,8 @@ pages generated by Doxygen:
   documented namespaces (and also Java packages).
 - The \c concept element represents the layout of all pages generated for
   documented concepts.
+- The \c module element represents the layout of all pages generated for
+  documented C++ modules.
 - The \c file element represents the layout of all pages generated for
   documented files.
 - The \c group element represents the layout of all pages generated for
@@ -320,6 +322,9 @@ The following generic elements are possible for each page:
   <dd>Represents the brief description on a page.
 <dt>\c detaileddescription
   <dd>Represents the detailed description on a page.
+</dl>
+The following generic element is possible for each page except the \c directory page:
+<dl>
 <dt>\c authorsection
   <dd>Represents the author section of a page (only used for man pages). This is
       a separate section for man pages with a text like:
@@ -328,21 +333,24 @@ The following generic elements are possible for each page:
       "\\author" or \ref cmdauthors "\\authors" that generate an author paragraph
       inside a detailed description.
 </dl>
-The following generic elements are possible for each page except the concept page:
+The following generic element is possible for each page except the \c concept page:
 <dl>
 <dt>\c memberdecl
   <dd>Represents the quick overview of members on a page (member declarations).
       This elements has child elements per type of member list.
       The possible child elements are not listed in detail in the document,
       but the name of the element should be a good indication of the type
       of members that the element represents.
+</dl>
+The following generic element is possible for each page except the \c concept and \c module page:
+<dl>
 <dt>\c memberdef
   <dd>Represents the detailed member list on a page (member definition).
       Like the \c memberdecl element, also this element has a number of
       possible child elements.
 </dl>
 
-The class page has the following specific elements:
+The \c class page has the following specific elements:
 <dl>
 <dt>\c includes
   <dd>Represents the include file needed to obtain the definition for
@@ -361,7 +369,7 @@ The class page has the following specific elements:
       extracted.
 </dl>
 
-The concept page has the following specific elements:
+The \c concept page has the following specific elements:
 <dl>
 <dt>\c includes
   <dd>Represents the include file needed to obtain the definition for
@@ -370,7 +378,7 @@ The concept page has the following specific elements:
   <dd>Represents the definition of the concept
 </dl>
 
-The file page has the following specific elements:
+The \c file page has the following specific elements:
 <dl>
 <dt>\c includes
   <dd>Represents the list of \#include statements contained in this file.
@@ -382,16 +390,19 @@ The file page has the following specific elements:
   <dd>Represents the link to the source code of this file.
 </dl>
 
-The group page has a specific \c groupgraph element which represents the
+The \c module page has a specific \c exportedmodules element which represents the
+modules that are exported from this module.
+
+The \c group page has a specific \c groupgraph element which represents the
 graph showing the dependencies between groups.
 
-Similarly, the directory page has a specific \c directorygraph element
+Similarly, the \c directory page has a specific \c directorygraph element
 which represents the graph showing the dependencies between the directories
 based on the \#include relations of the files inside the directories.
 
 Some elements have a \c visible attribute which can be
 used to hide the fragment from the generated output, by setting the attribute's
-value to "no". You can also use the value of a configuration option to
+value to \c no. You can also use the value of a configuration option to
 determine the visibility, by using
 its name prefixed with a dollar sign, e.g.
 \verbatim