Complex insert support

[lu-zero]

This adds support for more tokens and improves how vertical span mix with horizontal (hopefully)

[Copilot]

Pull Request Overview

This PR adds complex insert support to the SQL formatter, particularly improving how vertical spans mix with horizontal spans. The changes enhance tokenization support for SQL constructs like WINDOW clauses, DISTINCT FROM operators, ON CONFLICT clauses, and SET statements in UPDATE queries.

Key Changes:

• Adds new ReservedNewlineAfter token type for handling statements that need newlines after them
• Expands tokenizer support for additional SQL keywords and constructs
• Improves span tracking to better handle inline vs. multi-line formatting decisions

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/tokenizer.rs	Adds ReservedNewlineAfter token type and support for WINDOW, ON CONFLICT, PARTITION BY, and DISTINCT FROM keywords
src/lib.rs	Adds Debug trait to SpanInfo and includes comprehensive tests for new formatting features
src/indentation.rs	Updates indentation tracking to store SpanInfo alongside top-level tokens
src/formatter.rs	Implements formatting logic for ReservedNewlineAfter tokens and improves span-based formatting decisions

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