reflect scampi review

- fix README.md
- fix BadAttr doc
- is_rustfmt_macro_error => is_unknown_rustfmt_attr

Author: rchaser53

README.md

@@ -205,7 +205,7 @@ needs to be specified in `rustfmt.toml`, e.g., with `edition = "2018"`.
   | coverage | displays how much of the input file was processed | Yes |
   | checkstyle | emits in a checkstyle format | Yes |
 
-* For things you do not want rustfmt to mangle for some macro,
+* To prevent rustfmt from formatting a macro,
   use `#[rustfmt::skip::macros(target_macro_name)]`
 
   Example:

src/lib.rs

@@ -94,7 +94,7 @@ pub enum ErrorKind {
     /// Used deprecated skip attribute.
     #[fail(display = "`rustfmt_skip` is deprecated; use `rustfmt::skip`")]
     DeprecatedAttr,
-    /// Used a rustfmt:: attribute other than skip.
+    /// Used a rustfmt:: attribute other than skip or skip::macros.
     #[fail(display = "invalid attribute")]
     BadAttr,
     /// An io error during reading or writing.

src/visitor.rs

@@ -659,7 +659,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                         ErrorKind::DeprecatedAttr,
                     )],
                 );
-            } else if self.is_rustfmt_macro_error(&attr.path.segments) {
+            } else if self.is_unknown_rustfmt_attr(&attr.path.segments) {
                 let file_name = self.source_map.span_to_filename(attr.span).into();
                 self.report.append(
                     file_name,
@@ -687,7 +687,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         false
     }
 
-    fn is_rustfmt_macro_error(&self, segments: &[ast::PathSegment]) -> bool {
+    fn is_unknown_rustfmt_attr(&self, segments: &[ast::PathSegment]) -> bool {
         if segments[0].ident.to_string() != "rustfmt" {
             return false;
         }