Add small doc improvements in blob.rs, dense.rs

src/blob.rs

 use inflate::DeflateDecoder;
 
 
+/// The content type of a blob.
 #[derive(Debug, Eq, PartialEq)]
 pub enum BlobType<'a> {
+    /// Blob contains a `HeaderBlock`.
     OsmHeader,
+    /// Blob contains a `PrimitiveBlock`.
     OsmData,
+    /// An unknown blob type with the given string identifier.
+    /// Parsers should ignore unknown blobs they do not expect.
     Unknown(&'a str),
 }
 
 //TODO rename variants to fit proto files
+/// The decoded content of a blob (analogous to `BlobType`).
 pub enum BlobDecode<'a> {
+    /// Blob contains a `HeaderBlock`.
     OsmHeader(HeaderBlock),
+    /// Blob contains a `PrimitiveBlock`.
     OsmData(PrimitiveBlock),
+    /// An unknown blob type with the given string identifier.
+    /// Parsers should ignore unknown blobs they do not expect.
     Unknown(&'a str),
 }
 

src/dense.rs

 
 
 //TODO Add getter functions for id, version, uid, ...
-/// An OpenStreetMap node element from a compressed array of DenseNodes (See [OSM wiki](http://wiki.openstreetmap.org/wiki/Node)).
+/// An OpenStreetMap node element from a compressed array of dense nodes (See [OSM wiki](http://wiki.openstreetmap.org/wiki/Node)).
 pub struct DenseNode<'a> {
     block: &'a osmformat::PrimitiveBlock,