cmake: add comments for nice formatting
see
include (LibAddMacros)
-add_plugin (blockresolver SOURCES blockresolver.h blockresolver.c LINK_ELEKTRA elektra-invoke ADD_TEST INSTALL_TEST_DATA TEST_README)
+add_plugin (blockresolver #
+ SOURCES blockresolver.h
+ blockresolver.c #
+ LINK_ELEKTRA elektra-invoke #
+ ADD_TEST #
+ INSTALL_TEST_DATA #
+ TEST_README)
