First pass at trying to improve error message

Author: Jamesbarford

src/librustdoc/core.rs

@@ -403,11 +403,23 @@ pub(crate) fn run_global_ctxt(
             {}/rustdoc/how-to-write-documentation.html",
             crate::DOC_RUST_LANG_ORG_VERSION
         );
+
+        let krate_name = if let Some(name) = krate.module.inner.name {
+            format!("`{}`'s", name.as_str())
+        } else {
+            "this crate's".to_string()
+        };
+        let span = tcx.def_span(krate.module.item_id.as_local_def_id().unwrap());
+
         tcx.node_lint(
             crate::lint::MISSING_CRATE_LEVEL_DOCS,
             DocContext::as_local_hir_id(tcx, krate.module.item_id).unwrap(),
             |lint| {
-                lint.primary_message("no documentation found for this crate's top-level module");
+                lint.span(span);
+                lint.primary_message(format!(
+                    "no documentation found for {} top-level module",
+                    krate_name
+                ));
                 lint.help(help);
             },
         );