Minimize pub usage in source_map.rs.

Most notably, this commit changes the `pub use crate::*;` in that file
to `use crate::*;`. This requires a lot of `use` items in other crates
to be adjusted, because everything defined within `rustc_span::*` was
also available via `rustc_span::source_map::*`, which is bizarre.

The commit also removes `SourceMap::span_to_relative_line_string`, which
is unused.

Author: nnethercote

compiler/rustc_ast_lowering/src/expr.rs

@@ -15,9 +15,10 @@ use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::definitions::DefPathData;
 use rustc_session::errors::report_lit_error;
-use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
+use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::DUMMY_SP;
+use rustc_span::{DesugaringKind, Span};
 use thin_vec::{thin_vec, ThinVec};
 
 impl<'hir> LoweringContext<'_, 'hir> {

compiler/rustc_ast_lowering/src/item.rs

@@ -16,9 +16,8 @@ use rustc_hir::PredicateOrigin;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
 use rustc_span::edit_distance::find_best_match_for_name;
-use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::{Span, Symbol};
+use rustc_span::{DesugaringKind, Span, Symbol};
 use rustc_target::spec::abi;
 use smallvec::{smallvec, SmallVec};
 use thin_vec::ThinVec;