extend module documentation

modules/static_linking.cmake

@@ -1,3 +1,20 @@
+#.rst:
+#
+# Enables static linking by appending corresponding compiler flags.
+#
+# Variables modified (provided the corresponding language is enabled)::
+#
+#   CMAKE_Fortran_FLAGS
+#   CMAKE_C_FLAGS
+#   CMAKE_CXX_FLAGS
+#
+# Example autocmake.cfg entry::
+#
+#   [static_linking]
+#   source: https://github.com/scisoft/autocmake/raw/master/modules/static_linking.cmake
+#   docopt: --static Enable static linking [default: False].
+#   define: '-DENABLE_STATIC_LINKING=%s' % arguments['--static']
+
 option(ENABLE_STATIC_LINKING "Enable static libraries linking" OFF)
 
 if(ENABLE_STATIC_LINKING)