Clean up rustc_*/Cargo.toml.

- Sort dependencies and features sections.
- Add `tidy` markers to the sorted sections so they stay sorted.
- Remove empty `[lib`] sections.
- Remove "See more keys..." comments.

Excluded files:
- rustc_codegen_{cranelift,gcc}, because they're external.
- rustc_lexer, because it has external use.
- stable_mir, because it has external use.

compiler/rustc_parse/Cargo.toml

@@ -3,9 +3,8 @@ name = "rustc_parse"
 version = "0.0.0"
 edition = "2021"
 
-[lib]
-
 [dependencies]
+# tidy-alphabetical-start
 bitflags = "1.0"
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
@@ -21,3 +20,4 @@ thin-vec = "0.2.12"
 tracing = "0.1"
 unicode-normalization = "0.1.11"
 unicode-width = "0.1.4"
+# tidy-alphabetical-end