Fix tokenization of number literals in YAML lexer (#1239)

Stand-alone number literals in a block scalar are being tokenized as
`Literal::String` not as `Literal::Number`.

This commit fixes that while also ensuring that, if those literals are
preceded or succeeded by non-whitespace characters (that aren't
comments), they are tokenized as `Literal::String`.

Finally, the commit includes a change to ensure times are tokenized as
`Literal::String` (which is the existing behavior).

lib/rouge/lexers/yaml.rb

@@ -328,7 +328,7 @@ def set_indent(match, opts={})
       state :plain_scalar_in_block_context do
         # the : indicator ends a scalar
         rule %r/[ ]*(?=:[ \n]|:$)/, Text, :pop!
-        rule %r/[ ]*:/, Str
+        rule %r/[ ]*:\S+/, Str
         rule %r/[ ]+(?=#)/, Text, :pop!
         rule %r/[ ]+$/, Text
         # check for new documents or dedents at the new line
@@ -339,6 +339,8 @@ def set_indent(match, opts={})
 
         rule %r/[ ]+/, Str
         rule SPECIAL_VALUES, Name::Constant
+        rule %r/\d+(?:\.\d+)?(?=(\r?\n)| +#)/, Literal::Number, :pop!
+
         # regular non-whitespace characters
         rule %r/[^\s:]+/, Str
       end

spec/visual/samples/yaml

@@ -32,6 +32,7 @@ national:
   name: Mark McGwire
   hr:   65
   avg:  0.278
+  addr: B 221 Block
 -
   name: Sammy Sosa
   hr:   63