Fix mod-val regexp: method `getMods` didn't return all mods

Old regexp didn't match a block (elem) modifications which were fallowed one-by-one:
`b-test_mod-1_val b-test_mod-2_val b-test_mod-3_val b-test_mod-4_val b-test_mod-5_val`
for such className value was matched:
`["b-test_mod-1_val ", " b-test_mod-3_val ", " b-test_mod-5_val"]`
but classes `b-test_mod-2_val` and `b-test_mod-4_val` weren't matched.