replace missed occurrences of Extlib functions with Option

doc/developer/advance.tex

doc/developer/examples/syntactic_check.ml

doc/training/developer/annotations.tex

doc/training/developer/project.tex

src/kernel_internals/typing/cabs2cil.ml

tests/crowbar/complete_type.ml

tests/misc/add_assigns.ml

tests/misc/exception.ml

tests/misc/find_enclosing_loop.ml

tests/misc/my_visitor.ml

tests/misc/static.ml

tests/misc/vis_spec.ml

tests/spec/location_char.ml

tests/spec/logic_functions_sets.ml

tests/spec/property_test.ml

tests/syntax/copy_visitor_bts_1073.ml

tests/syntax/transient_block.ml

tests/syntax/visit_create_local.ml