tutorial: add array module warnings when needed

doc/Doxyfile.in

@@ -206,7 +206,9 @@ ALIASES                = "only_for_vectors=This is only for vectors (either row-
                          "geometry_module=This is defined in the %Geometry module. \code #include <Eigen/Geometry> \endcode" \
                          "regression_module=This is defined in the %Regression module. \code #include <Eigen/Regression> \endcode" \
                          "addexample=\anchor"  \
-                         "label=\bug"
+                         "label=\bug" \
+                         "redstar=<a href='#warningarraymodule' style='color:red;text-decoration: none;'><span style='color:red'>*</span></a>"
+
 # Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C
 # sources only. Doxygen will then generate output that is more tailored for C.
 # For instance, some of the names that are used will be different. The list
@@ -584,7 +586,7 @@ RECURSIVE              = NO
 # excluded from the INPUT source files. This way you can easily exclude a
 # subdirectory from a directory tree whose root is specified with the INPUT tag.
 
-EXCLUDE                = 
+EXCLUDE                =
 
 # The EXCLUDE_SYMLINKS tag can be used select whether or not files or
 # directories that are symbolic links (a Unix filesystem feature) are excluded
@@ -776,7 +778,7 @@ HTML_HEADER             = ${EIGEN_BINARY_DIR}/doc/eigendoxy_header.html
 
 # the footer has not been customized yet, so let's use the default one
 # ${EIGEN_BINARY_DIR}/doc/eigendoxy_footer.html
-HTML_FOOTER             = 
+HTML_FOOTER             =
 
 # The HTML_STYLESHEET tag can be used to specify a user-defined cascading
 # style sheet that is used by each HTML page. It can be used to