Re-export more rustc_span::symbol things from rustc_span.

`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.

This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.

compiler/rustc_interface/src/interface.rs

@@ -22,9 +22,8 @@ use rustc_session::config::{self, Cfg, CheckCfg, ExpectedValues, Input, OutFileN
 use rustc_session::filesearch::{self, sysroot_candidates};
 use rustc_session::parse::ParseSess;
 use rustc_session::{CompilerIO, EarlyDiagCtxt, Session, lint};
-use rustc_span::FileName;
 use rustc_span::source_map::{FileLoader, RealFileLoader, SourceMapInputs};
-use rustc_span::symbol::sym;
+use rustc_span::{FileName, sym};
 use tracing::trace;
 
 use crate::util;

compiler/rustc_interface/src/passes.rs

@@ -32,8 +32,7 @@ use rustc_session::cstore::Untracked;
 use rustc_session::output::{collect_crate_types, filename_for_input, find_crate_name};
 use rustc_session::search_paths::PathKind;
 use rustc_session::{Limit, Session};
-use rustc_span::symbol::{Symbol, sym};
-use rustc_span::{ErrorGuaranteed, FileName, SourceFileHash, SourceFileHashAlgorithm};
+use rustc_span::{ErrorGuaranteed, FileName, SourceFileHash, SourceFileHashAlgorithm, Symbol, sym};
 use rustc_target::spec::PanicStrategy;
 use rustc_trait_selection::traits;
 use tracing::{info, instrument};

compiler/rustc_interface/src/proc_macro_decls.rs

@@ -2,7 +2,7 @@ use rustc_ast::attr;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
-use rustc_span::symbol::sym;
+use rustc_span::sym;
 
 fn proc_macro_decls_static(tcx: TyCtxt<'_>, (): ()) -> Option<LocalDefId> {
     let mut decls = None;

compiler/rustc_interface/src/tests.rs

@@ -23,8 +23,7 @@ use rustc_session::utils::{CanonicalizedPath, NativeLib, NativeLibKind};
 use rustc_session::{CompilerIO, EarlyDiagCtxt, Session, build_session, filesearch, getopts};
 use rustc_span::edition::{DEFAULT_EDITION, Edition};
 use rustc_span::source_map::{RealFileLoader, SourceMapInputs};
-use rustc_span::symbol::sym;
-use rustc_span::{FileName, SourceFileHashAlgorithm};
+use rustc_span::{FileName, SourceFileHashAlgorithm, sym};
 use rustc_target::spec::{
     CodeModel, FramePointer, LinkerFlavorCli, MergeFunctions, OnBrokenPipe, PanicStrategy,
     RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel, WasmCAbi,

compiler/rustc_interface/src/util.rs

@@ -18,7 +18,7 @@ use rustc_session::{EarlyDiagCtxt, Session, filesearch};
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::edition::Edition;
 use rustc_span::source_map::SourceMapInputs;
-use rustc_span::symbol::sym;
+use rustc_span::sym;
 use rustc_target::spec::Target;
 use tracing::info;