Use empty range when there's "gap" in token source

[dhruvmanila]

Summary

This fixes a bug where the parser would panic when there is a "gap" in
the token source.

What's a gap?

The reason it's <= instead of just == is because there could be whitespaces between
the two tokens. For example:

#     last token end
#     | current token (newline) start
#     v v
def foo \n
#      ^
#      assume there's trailing whitespace here

Or, there could tokens that are considered "trivia" and thus aren't emitted by the token
source. These are comments and non-logical newlines. For example:

#     last token end
#     v
def foo # comment\n
#                ^ current token (newline) start

In either of the above cases, there's a "gap" between the end of the last token and start
of the current token.

Test Plan

Add test cases and update the snapshots.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+0 -1 violations, +0 -0 fixes in 1 projects; 43 projects unchanged)

python/typeshed (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview --select E,F,FA,I,PYI,RUF,UP,W

- stdlib/pathlib.pyi:111:89: E999 SyntaxError: Expected ':', found newline

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
E999	1	0	1	0	0

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[MichaReiser]

Nit: i think this is specific to error recovery and instead is true for all "empty" nodes that don't consist of any tokens?

If that's the case, then I think we can remove the missing_node_range method that was only added to handle empty node ranges.

[dhruvmanila]

I think missing_node_range is still useful in places where you don't have the start value or rather the start value itself is the current token start.