YangTools grammar misses unknown statement in some statements

Based on YANG grammar review, these statements in YangTools grammar miss unknown statement, wrapped in statement separator (stmtsep):

submodule-stmt
import-stmt
include-stmt
belongs-to-stmt
revision-stmt

Example to compare and understand:

RFC6020:
submodule-stmt = optsep submodule-keyword sep identifier-arg-str
optsep
"

{" stmtsep submodule_header_stmts linkage_stmts meta_stmts revision_stmts body_stmts '}

' optsep;

as opposed to:

YangTools (YangParser.g4):
submodule_stmt : SUBMODULE_KEYWORD string
LEFT_BRACE
submodule_header_stmts
linkage_stmts
meta_stmts
revision_stmts
body_stmts
RIGHT_BRACE;