Cleaned up a few doc comments in libfmt_macros.

Author: Alexander Regueiro

src/libfmt_macros/lib.rs

@@ -410,7 +410,7 @@ impl<'a> Parser<'a> {
  &self.input[start..self.input.len()]
  }
 
- /// Parses an Argument structure, or what's contained within braces inside the format string
+ /// Parses an `Argument` structure, or what's contained within braces inside the format string.
  fn argument(&mut self) -> Argument<'a> {
  let pos = self.position();
  let format = self.format();
@@ -464,7 +464,7 @@ impl<'a> Parser<'a> {
  }
 
  /// Parses a format specifier at the current position, returning all of the
- /// relevant information in the FormatSpec struct.
+ /// relevant information in the `FormatSpec` struct.
  fn format(&mut self) -> FormatSpec<'a> {
  let mut spec = FormatSpec {
  fill: None,
@@ -571,7 +571,7 @@ impl<'a> Parser<'a> {
  spec
  }
 
- /// Parses a Count parameter at the current position. This does not check
+ /// Parses a `Count` parameter at the current position. This does not check
  /// for 'CountIsNextParam' because that is only used in precision, not
  /// width.
  fn count(&mut self, start: usize) -> (Count, Option<InnerSpan>) {