Created .C files corresponding to the <application>.L files for Doxygen and -doc option

Resolves bug-report https://bugs.openfoam.org/view.php?id=3070

doc/Doxygen/Doxyfile

@@ -793,9 +793,7 @@ INPUT_ENCODING         = UTF-8
 # *.m, *.markdown, *.md, *.mm, *.dox, *.py, *.f90, *.f, *.for, *.tcl, *.vhd,
 # *.vhdl, *.ucf, *.qsf, *.as and *.js.
 
-FILE_PATTERNS          = *.H \
-                         *.C \
-                         *.L
+FILE_PATTERNS          = *.H *.C
 
 # The RECURSIVE tag can be used to specify whether or not subdirectories should
 # be searched for input files as well.