Quote reserved keywords in PostgreSQL function update fragments

[MarkVDD]

Description

The Problem

PostgreSQL reserved keywords (such as offset, limit, all, and select) cause a PostgresException (42601): syntax error when used as column names in generated PL/pgSQL functions. This happens because the SQL generator in TableColumn was using the raw Name property instead of a delimited identifier in the SET clause of update statements.

Example of failing SQL:
ON CONFLICT (id) DO UPDATE SET offset = EXCLUDED.offset; -- Syntax error near 'offset'

The Fix

Updated TableColumn.ToFunctionUpdate() to use the QuotedName property. This ensures that column assignments inside internal functions are always safely wrapped in double quotes (e.g., "offset" = p_offset).

Changes

• Core: Modified Weasel.Postgresql.Tables.TableColumn.ToFunctionUpdate() to use quoted identifiers.
• Unit Test: Added a Theory test to_function_update_should_quote_reserved_keywords in TableColumnTests.cs to verify string generation for common keywords.
• Integration Test: Added a comprehensive Theory in detecting_table_deltas.cs that iterates through 70+ PostgreSQL reserved keywords to ensure they work across the full DDL lifecycle without triggering "infinite migrations" (false deltas).

Verification

• Unit tests pass.
• Integration tests with a live Postgres database pass.
• Verified that detecting_table_deltas.no_delta remains green, ensuring no regression in schema comparison logic.

Related Marten PR: JasperFx/marten#4237