Revises Buf for #2709, minor changes

Also adds missing methods for Blob. Refs #2694.

doc/Type/Blob.pod6

@@ -76,15 +76,40 @@ Returns the number of bytes used by the elements in the buffer.
     say blob16.new([1, 2, 3]).bytes;    # OUTPUT: «6␤»
     say blob64.new([1, 2, 3]).bytes;    # OUTPUT: «24␤»
 
+=head2 method chars
+
+Defined as:
+
+    method chars(Blob:D:)
+
+Throws C<X::Buf::AsStr> with C<chars> as payload.
+
+=head2 method Str
+
+Defined as:
+
+    multi method Str(Blob:D:)
+
+Throws C<X::Buf::AsStr> with C<Str> as payload. In order to convert to a C<Str>
+you need to use L<C<.decode>|/routine/decode>.
+
+=head2 method Stringy
+
+Defined as:
+
+    multi method Stringy(Blob:D:)
+
+Throws C<X::Buf::AsStr> with C<Stringy> as payload.
+
 =head2 method decode
 
 Defined as:
 
     multi method decode(Blob:D: $encoding = self.encoding // "utf-8")
 
 =for code :method
-    multi method decode(Blob:D: $encoding, Str :$replacement!,
-                        Bool:D :$strict = False)
+multi method decode(Blob:D: $encoding, Str :$replacement!,
+                    Bool:D :$strict = False)
 
     multi method decode(Blob:D: $encoding, Bool:D :$strict = False)
 

doc/Type/Buf.pod6

@@ -4,9 +4,9 @@
 
 =SUBTITLE Mutable buffer for binary data
 
-    role Buf[::T] does Blob[T] { ... }
+    role Buf[::T = uint8] does Blob[T] is repr('VMArray') is array_type(T){ ... }
 
-A C<Buf> is a mutable sequence of (usually unsigned) integers.
+A C<Buf> does the role of a mutable sequence of (usually unsigned) integers.
 
     my $b = Buf.new(1, 2, 3);
     $b[1] = 42;