lcovrc.5: Add genhtml_demangle_cpp default and CLI reference

Signed-off-by: Peter Oberparleiter <[email protected]>

Author: oberpar

man/lcovrc.5

@@ -572,6 +572,13 @@ names to human readable format for display on the HTML function overview
 page.  This option requires that the c++filt tool is installed (see
 .BR c++filt(1)
 ).
+.br
+
+This option corresponds to the \-\-demangle\-cpp command line option of
+.BR genhtml .
+.br
+
+Default is 0.
 .PP
 
 .BR genhtml_desc_html " ="