Auto merge of #15559 - Veykril:builtin-format-args, r=Veykril

Implement builtin#format_args, using rustc's format_args parser

`format_args!` now expands to `builtin#format_args(template, args...)`, the actual expansion now instead happens in lowering where we desugar this expression by using lang paths.

As a bonus, we no longer need to evaluate `format_args` as an eager macro which means less macro expansions overall -> less cache thrashing!

Fixes #15082

Author: bors

Cargo.lock

@@ -33,6 +33,7 @@ triomphe.workspace = true
 
 rustc_abi = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_abi", default-features = false }
 rustc_index = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_index", default-features = false }
+rustc_lexer = { version = "0.1.0", package = "ra-ap-rustc_lexer" }
 
 # local deps
 stdx.workspace = true