Fix task-list checkbox styling (#10668)

* Fix task-list checkbox styling

The pandoc renderer will append the class "task-list" to the ul element
wrapping a li with one or more check-boxes. This allows us to select for
them, removing their list-style-type property. However, goldmark and the
gfm spec doesn't specify the "task-list" class name, so we can't use
that to fix the issue there.

Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com>

* Update to goldmark v1.1.25

This version adds the missing space after a checkbox.

Resolves: #9656

Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com>

Co-authored-by: zeripath <art27@cantab.net>

go.mod

 	github.com/unknwon/paginater v0.0.0-20151104151617-7748a72e0141
 	github.com/urfave/cli v1.20.0
 	github.com/yohcop/openid-go v0.0.0-20160914080427-2c050d2dae53
-	github.com/yuin/goldmark v1.1.24
+	github.com/yuin/goldmark v1.1.25
 	go.etcd.io/bbolt v1.3.3 // indirect
 	golang.org/x/crypto v0.0.0-20200221231518-2aa609cf4a9d
 	golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa

go.sum

 github.com/yohcop/openid-go v0.0.0-20160914080427-2c050d2dae53/go.mod h1:f6elajwZV+xceiaqgRL090YzLEDGSbqr3poGL3ZgXYo=
 github.com/yuin/goldmark v1.1.24 h1:K4FemPDr4x/ZcqldoXWnexTLfdMIy2eEfXxsLnotTRI=
 github.com/yuin/goldmark v1.1.24/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/ziutek/mymysql v1.5.4 h1:GB0qdRGsTwQSBVYuVShFBKaXSnSnYYC2d9knnE1LHFs=
 github.com/ziutek/mymysql v1.5.4/go.mod h1:LMSpPZ6DbqWFxNCHW77HeMg9I646SAhApZ/wKdgO/C0=
 go.etcd.io/bbolt v1.3.2/go.mod h1:IbVyRI1SCnLcuJnV2u8VeU0CEYM7e686BmAb1XKL+uU=

modules/markup/sanitizer.go

 	// Allow classes for anchors
 	sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue`)).OnElements("a")
 
+	// Allow classes for task lists
+	sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list`)).OnElements("ul")
+
 	// Allow generally safe attributes
 	generalSafeAttrs := []string{"abbr", "accept", "accept-charset",
 		"accesskey", "action", "align", "alt",

vendor/github.com/yuin/goldmark/extension/tasklist.go

 		w.WriteString(`<input disabled="" type="checkbox"`)
 	}
 	if r.XHTML {
-		w.WriteString(" />")
+		w.WriteString(" /> ")
 	} else {
-		w.WriteString(">")
+		w.WriteString("> ")
 	}
 	return gast.WalkContinue, nil
 }

vendor/github.com/yuin/goldmark/parser/list.go

 		}
 		return Continue | HasChildren
 	}
-	// Thematic Breaks take precedence over lists
-	if isThematicBreak(line, reader.LineOffset()) {
-		isHeading := false
-		last := pc.LastOpenedBlock().Node
-		if ast.IsParagraph(last) {
-			c, ok := matchesSetextHeadingBar(line)
-			if ok && c == '-' {
-				isHeading = true
-			}
-		}
-		if !isHeading {
-			return Close
-		}
-	}
 
 	// "offset" means a width that bar indicates.
 	//    -  aaaaaaaa
 				if !list.CanContinue(marker, typ == orderedList) {
 					return Close
 				}
+				// Thematic Breaks take precedence over lists
+				if isThematicBreak(line[match[3]-1:], 0) {
+					isHeading := false
+					last := pc.LastOpenedBlock().Node
+					if ast.IsParagraph(last) {
+						c, ok := matchesSetextHeadingBar(line)
+						if ok && c == '-' {
+							isHeading = true
+						}
+					}
+					if !isHeading {
+						return Close
+					}
+				}
+
 				return Continue | HasChildren
 			}
 		}

vendor/modules.txt

 github.com/xanzy/ssh-agent
 # github.com/yohcop/openid-go v0.0.0-20160914080427-2c050d2dae53
 github.com/yohcop/openid-go
-# github.com/yuin/goldmark v1.1.24
+# github.com/yuin/goldmark v1.1.25
 github.com/yuin/goldmark
 github.com/yuin/goldmark/ast
 github.com/yuin/goldmark/extension

web_src/less/_markdown.less

         list-style-type: none;
     }
 
+    ul.task-list,
+    ol.task-list {
+        list-style-type: none;
+    }
+
     ul ul,
     ul ol,
     ol ol,