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]

[yigalrozenberg]

Thank you for this contribution, @gauravs!

This is a clean, well-tested improvement. Making generate_pretty honor the target dialect (instead of silently falling back to source/ANSI quoting) is a nice correctness win, and exposing sqlglot_generate_pretty through the FFI — with matching C/C++ examples and docs — rounds it out really well. The two new test files made verification straightforward.

Merged and released in v0.10.21, now live on crates.io.

One small adjustment on merge: since master had already advanced to 0.10.20, I resolved the version bump to 0.10.21 and updated the #[deprecated(since = ...)] note on Generator::pretty to match the actual release version. Everything else went in exactly as you wrote it.

Thanks again for helping improve sqlglot-rust!