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_errors/Cargo.toml

@@ -3,29 +3,29 @@ name = "rustc_errors"
 version = "0.0.0"
 edition = "2021"
 
-[lib]
-
 [dependencies]
-tracing = "0.1"
+# tidy-alphabetical-start
+annotate-snippets = "0.9"
+derive_setters = "0.1.6"
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
+rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_error_messages = { path = "../rustc_error_messages" }
 rustc_fluent_macro = { path = "../rustc_fluent_macro" }
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_span = { path = "../rustc_span" }
-rustc_macros = { path = "../rustc_macros" }
-rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_target = { path = "../rustc_target" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
+rustc_macros = { path = "../rustc_macros" }
+rustc_serialize = { path = "../rustc_serialize" }
+rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
 rustc_type_ir = { path = "../rustc_type_ir" }
-unicode-width = "0.1.4"
-termcolor = "1.2.0"
-annotate-snippets = "0.9"
-termize = "0.1.1"
 serde = { version = "1.0.125", features = [ "derive" ] }
 serde_json = "1.0.59"
-derive_setters = "0.1.6"
+termcolor = "1.2.0"
+termize = "0.1.1"
+tracing = "0.1"
+unicode-width = "0.1.4"
+# tidy-alphabetical-end
 
 [target.'cfg(windows)'.dependencies.windows]
 version = "0.48.0"
@@ -36,4 +36,6 @@ features = [
 ]
 
 [features]
+# tidy-alphabetical-start
 rustc_use_parallel_compiler = ['rustc_error_messages/rustc_use_parallel_compiler']
+# tidy-alphabetical-end