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.

3 files changed, 3 insertions, 6 deletions

diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index 031c50c45d4..569034954c3 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -47,8 +47,7 @@ use rustc_middle::dep_graph::{
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::{bug, span_bug};
-use rustc_span::Span;
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 use tracing::debug;
 use {rustc_graphviz as dot, rustc_hir as hir};
 
diff --git a/compiler/rustc_incremental/src/errors.rs b/compiler/rustc_incremental/src/errors.rs
index cb21f975878..b4a207386dc 100644
--- a/compiler/rustc_incremental/src/errors.rs
+++ b/compiler/rustc_incremental/src/errors.rs
@@ -1,8 +1,7 @@
 use std::path::{Path, PathBuf};
 
 use rustc_macros::Diagnostic;
-use rustc_span::symbol::Ident;
-use rustc_span::{Span, Symbol};
+use rustc_span::{Ident, Span, Symbol};
 
 #[derive(Diagnostic)]
 #[diag(incremental_unrecognized_depnode)]
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index a85686e590b..b99872e7ae6 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -29,8 +29,7 @@ use rustc_hir::{
 use rustc_middle::dep_graph::{DepNode, DepNodeExt, label_strs};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
-use rustc_span::Span;
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 use thin_vec::ThinVec;
 use tracing::debug;