fix minor problems for icfd document

Author: zhangzhanqun

examples/ICFD/icfd_dem_coupling.py

@@ -2,7 +2,7 @@
 DEM Coupling
 ============
 
-This example shows how to couple the ICFD fluid solver with DEM particles.
+This example shows how to couple the ICFD fluid solver with DEM particles. \n
 LS-DYNA version : ls-dyna_smp_d_R101_winx64_ifort131.exe
 """
 

examples/ICFD/icfd_driven_cavity.py

@@ -2,7 +2,7 @@
 Driven cavity
 =============
 
-This example shows the universally famous driven cavity case tested with the second order steady solver and for Re=1000.
+This example shows the universally famous driven cavity case tested with the second order steady solver and for Re=1000. \n
 LS-DYNA version : ls-dyna_smp_d_R13.1_138-g8429c8a10f_winx64_ifort190.exe
 """
 

examples/ICFD/icfd_free_convection_flow.py

@@ -2,7 +2,7 @@
 Thermal flow
 ============
 
-This example shows a simple ICFD forced convection input deck with a coarse mesh.
+This example shows a simple ICFD forced convection input deck with a coarse mesh. \n
 LS-DYNA version : ls-dyna_smp_d_R13.1_138-g8429c8a10f_winx64_ifort190.exe
 """