Snowflake: preserve reluctant MATCH_RECOGNIZE quantifiers

[osipovartem]

What does this PR do?

Preserves the reluctant modifier on Snowflake/SQL MATCH_RECOGNIZE quantifiers. Previously, A*? was represented as (A*)?, changing a reluctant zero-or-more quantifier into a nested optional repetition.

The AST now represents this as Repetition(A, Reluctant(ZeroOrMore)). Existing Repetition(pattern, quantifier) construction remains unchanged. The Reluctant wrapper also covers +?, ??, and range forms such as {2,4}?; unsupported stacked quantifiers are rejected.

Reference

Snowflake documents the reluctant suffix, its non-greedy semantics, and the supported forms in the MATCH_RECOGNIZE pattern syntax.

Tests

• cargo +1.95.0 test --offline --all-features --test sqlparser_common test_match_recognize_patterns (passed after rebase)
• The focused test and formatting check passed after rebase. The full all-features suite and upstream CI passed before rebase; current CI is running on the rebased commit.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.44444% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.98%. Comparing base (6862e71) to head (cd4a3fd).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/parser/mod.rs	68.57%	3 Missing and 8 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2510      +/-   ##
==========================================
+ Coverage   80.96%   80.98%   +0.01%     
==========================================
  Files          42       42              
  Lines       33386    33392       +6     
  Branches    33386    33392       +6     
==========================================
+ Hits        27032    27043      +11     
  Misses       2789     2789              
+ Partials     3565     3560       -5     

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[LucaCappelletti94]

LGTM! The missing lines are all error cases that I think is okay to leave be.
cc @alamb @iffyio