Revert commonmark spec to 0.13

Previous update was to one from master branch,
which resulted in one more broken test.

test/fixtures/commonmark/bad.txt

@@ -1,21 +1,5 @@
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 4463
+src line: 5513
-
-.
-* a *
-.
-<p>* a *</p>
-.
-
-error:
-
-<ul>
-<li>a *</li>
-</ul>
-
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 5521
 
 .
 [foo [bar](/uri)](/uri)
@@ -29,7 +13,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 5527
+src line: 5519
 
 .
 [foo *[bar [baz](/uri)](/uri)*](/uri)
@@ -43,7 +27,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 5648
+src line: 5640
 
 .
 [foo [bar](/uri)][ref]
@@ -59,7 +43,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 5656
+src line: 5648
 
 .
 [foo *bar [baz][ref]*][ref]
@@ -75,7 +59,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 5923
+src line: 5915
 
 .
 [foo] bar
@@ -91,7 +75,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6028
+src line: 6020
 
 .
 ![foo *bar*]
@@ -107,7 +91,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6036
+src line: 6028
 
 .
 ![foo ![bar](/url)](/url2)
@@ -121,7 +105,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6042
+src line: 6034
 
 .
 ![foo [bar](/url)](/url2)
@@ -135,7 +119,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6055
+src line: 6047
 
 .
 ![foo *bar*][]
@@ -151,7 +135,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6063
+src line: 6055
 
 .
 ![foo *bar*][foobar]
@@ -167,7 +151,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6123
+src line: 6115
 
 .
 ![*foo* bar][]
@@ -183,7 +167,7 @@ error:
 
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6163
+src line: 6155
 
 .
 ![*foo* bar]

test/fixtures/commonmark/spec.txt

@@ -948,19 +948,18 @@ use backslash escapes:
 
 ## Indented code blocks
 
-An [indented code block](@indented-code-block) is composed of one or more
+An [indented code block](@indented-code-block)
+is composed of one or more
 [indented chunks](#indented-chunk) separated by blank lines.
-An [indented chunk](@indented-chunk) is a sequence of non-blank lines,
+An [indented chunk](@indented-chunk)
-each indented four or more spaces. The contents of the code block are
+is a sequence of non-blank lines, each indented four or more
+spaces.  An indented code block cannot interrupt a paragraph, so
+if it occurs before or after a paragraph, there must be an
+intervening blank line.  The contents of the code block are
 the literal contents of the lines, including trailing newlines,
 minus four spaces of indentation. An indented code block has no
 attributes.
 
-An indented code block cannot interrupt a paragraph, so there must be
-a blank line between a paragraph and a following indented code block.
-(A blank line is not needed, however, between a code block and a following
-paragraph.)
-
 .
     a simple
       indented code block
@@ -4355,8 +4354,8 @@ The following rules capture all of these patterns, while allowing
 for efficient parsing strategies that do not backtrack:
 
 1.  A single `*` character [can open emphasis](@can-open-emphasis)
-    iff it is not followed by whitespace.  (For these purposes,
+    iff it is not followed by
-    any unicode space character counts as whitespace.)
+    whitespace.
 
 2.  A single `_` character [can open emphasis](#can-open-emphasis) iff
     it is not followed by whitespace and it is not preceded by an
@@ -4378,7 +4377,8 @@ for efficient parsing strategies that do not backtrack:
     ASCII alphanumeric character.
 
 7.  A double `**` [can close strong emphasis](@can-close-strong-emphasis)
-    iff it is not preceded by whitespace.
+    iff it is not preceded by
+    whitespace.
 
 8.  A double `__` [can close strong emphasis](#can-close-strong-emphasis)
     iff it is not preceded by whitespace and it is not followed by an
@@ -4458,14 +4458,6 @@ a * foo bar*
 <p>a * foo bar*</p>
 .
 
-Unicode nonbreaking spaces count as whitespace, too:
-
-.
-* a *
-.
-<p>* a *</p>
-.
-
 Intraword emphasis with `*` is permitted:
 
 .