feat(ffi): expose sqlglot_generate_pretty with dialect-aware formatting

[gauravs]

Adds pretty-printing to the FFI and fixes generate_pretty to actually respect the target dialect.

Previously generate_pretty(ast, dialect) ignored its dialect argument, so formatted output always used source/ANSI quoting instead of the target's.

Changes

• Fix generate_pretty to honor the target dialect
• Add Generator::generate_pretty method; deprecate Generator::pretty
• New FFI export sqlglot_generate_pretty; update C/C++ examples and docs
• Bump 0.10.17

Before / after

Parsing MySQL and pretty-printing as T-SQL:

let ast = parse("SELECT `select` FROM `events`", Dialect::Mysql).unwrap();
let out = generate_pretty(&ast, Dialect::Tsql);

// Before — dialect ignored, MySQL backticks leak through:
SELECT
  `select`
FROM
  `events`

// After — normalized to T-SQL quoting:
SELECT
  [select]
FROM
  [events]