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_mir_dataflow/Cargo.toml

@@ -3,13 +3,10 @@ name = "rustc_mir_dataflow"
 version = "0.0.0"
 edition = "2021"
 
-[lib]
-
 [dependencies]
+# tidy-alphabetical-start
 polonius-engine = "0.13.0"
 regex = "1"
-smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
-tracing = "0.1"
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
@@ -20,5 +17,8 @@ rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
-rustc_target = { path = "../rustc_target" }
 rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
+smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+tracing = "0.1"
+# tidy-alphabetical-end