This PR adds a script to update sql function doc pages based on the output of duckdb_functions().
Page docs/sql/functions/blob.md was created to show its functionality, and uses the category labels introduced in duckdb/duckdb#15654

Dependencies

• script generate_sql_function_docs.py requires a duckdb version that includes PR 15654, which introduces the 'categories' label to the output of duckdb_functions(). (not yet merged as of now)

Settings

script generate_sql_function_docs.py has a number of hard coded settings that will probably change or move to a config file in the future:

• DOC_CATEGORY_MAP - lists which doc pages will be generated, and which category from duckdb_functions() applies
• BINARY_OPERATORS - lists 'functions' that are binary operators, which are listed between the arguments
• OVERRIDES_MAP - hardcoded overrides and additions relative to the duckdb_functions() outputs:
  • for now: use for table_functions / macros, since they are not yet covered by duckdb_functions()
  • use for functions (like ||) that use parameter_types = ANY. (Ideally these functions should be implemented as a ScalarFunctionSet, so the supported function overloads can be explicitly outputted by duckdb_functions()
• URL_CONVERSIONS - adds url links to the function descriptions, as they are not present in the duckdb_functions() output
• FIXED_EXAMPLES - contains fixed example results, for examples that can not be run independently (e.g. because they are dependent on an input file or the existence of specific data tables)

Limitations

• alias information is not yet available in the output of duckdb_functions(), so is currently missing from generated doc pages
• table functions and macros can only be added manually via OVERRIDES_MAP, since they are not properly listed by duckdb_functions()
• displaying multiple examples is currently not supported, even though this information is available via duckdb_functions()