feat(snowflake)!: normalize FLOAT to DOUBLE

[toriwei]

In Snowflake, parse FLOAT to its synonym DOUBLE.

This will improve transpilation to DuckDB, as Snowflake double-precision FLOAT will get mapped to DuckDB DOUBLE, rather than DuckDB's single-precision REAL

Previously:

Snowflake -> DuckDB
CAST(6.43 AS FLOAT) → CAST(6.43 AS REAL))

Now:

Snowflake -> DuckDB
CAST(6.43 AS FLOAT) → CAST(6.43 AS DOUBLE))

[github-actions]

SQLGlot Integration Test Results

Comparing:

• this branch (sqlglot:tori/map-float-to-double-snowflake, sqlglot version: tori/map-float-to-double-snowflake)
• baseline (main, sqlglot version: 28.1.1.dev72)

⚠️ Limited to dialects: snowflake

By Dialect

dialect	main	sqlglot:tori/map-float-to-double-snowflake	difference	links
snowflake -> duckdb	49/1583 passed (3.1%)	49/1583 passed (3.1%)	No change	full result / delta
snowflake -> snowflake	88/1583 passed (5.6%)	88/1583 passed (5.6%)	No change	full result / delta

Overall

main: 3166 total, 137 passed (pass rate: 4.3%), sqlglot version: 28.1.1.dev72

sqlglot:tori/map-float-to-double-snowflake: 3166 total, 137 passed (pass rate: 4.3%), sqlglot version: tori/map-float-to-double-snowflake

Difference: No change

[georgesittas]

One comment, feel free to merge otherwise.