Dynamic Earley: Incorrect value for SymbolNode.end

[chanicpanic]

Consider the following:

grammar = r"""
start: "ABC"
"""

print(Lark(grammar, ambiguity="forest").parse("ABC"))

Output: (start, 0, 2, -inf)

The end index is 2 which suggests that the substring "AB" was parsed. However, we know that the full string was parsed, so the end index should be 3.

Note that the issue does not occur if we use a rule instead:

grammar = r"""
start: abc 
abc: "ABC"
"""

print(Lark(grammar, ambiguity="forest").parse("ABC"))

Output: (start, 0, 3, -inf)

I will open a PR with a fix.