go/doc/comment: support links in lists in comments

The proposed (golang#51082) new go doc comment additions supports lists,
links, and doc links, but does not support links and doc links inside
lists, so implemnent this.

Fixes golang#53610

Change-Id: I4fa17d204fc9efa8f3633133e4a49e56cf1aa9bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/415174
Reviewed-by: Ben Golightly <golightly.ben@googlemail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>

src/go/doc/comment/parse.go

@@ -326,6 +326,13 @@ func (p *Parser) Parse(text string) *Doc {
 		switch b := b.(type) {
 		case *Paragraph:
 			b.Text = d.parseLinkedText(string(b.Text[0].(Plain)))
+		case *List:
+			for _, i := range b.Items {
+				for _, c := range i.Content {
+					p := c.(*Paragraph)
+					p.Text = d.parseLinkedText(string(p.Text[0].(Plain)))
+				}
+			}
 		}
 	}
 

src/go/doc/comment/testdata/linklist.txt

@@ -0,0 +1,18 @@
+{"DocLinkBaseURL": "https://pkg.go.dev"}
+-- input --
+Did you know?
+
+  - [encoding/json.Marshal] is a doc link. So is [encoding/json.Unmarshal].
+-- text --
+Did you know?
+
+  - encoding/json.Marshal is a doc link. So is encoding/json.Unmarshal.
+-- markdown --
+Did you know?
+
+  - [encoding/json.Marshal](https://pkg.go.dev/encoding/json#Marshal) is a doc link. So is [encoding/json.Unmarshal](https://pkg.go.dev/encoding/json#Unmarshal).
+-- html --
+<p>Did you know?
+<ul>
+<li><a href="https://pkg.go.dev/encoding/json#Marshal">encoding/json.Marshal</a> is a doc link. So is <a href="https://pkg.go.dev/encoding/json#Unmarshal">encoding/json.Unmarshal</a>.
+</ul>

src/go/doc/comment/testdata/linklist2.txt

@@ -0,0 +1,39 @@
+{"DocLinkBaseURL": "https://pkg.go.dev"}
+-- input --
+Did you know?
+
+  - [testing.T] is one doc link.
+  - So is [testing.M].
+  - So is [testing.B].
+    This is the same list paragraph.
+
+    There is [testing.PB] in this list item, too!
+-- text --
+Did you know?
+
+  - testing.T is one doc link.
+
+  - So is testing.M.
+
+  - So is testing.B. This is the same list paragraph.
+
+    There is testing.PB in this list item, too!
+-- markdown --
+Did you know?
+
+  - [testing.T](https://pkg.go.dev/testing#T) is one doc link.
+
+  - So is [testing.M](https://pkg.go.dev/testing#M).
+
+  - So is [testing.B](https://pkg.go.dev/testing#B). This is the same list paragraph.
+
+    There is [testing.PB](https://pkg.go.dev/testing#PB) in this list item, too!
+-- html --
+<p>Did you know?
+<ul>
+<li><p><a href="https://pkg.go.dev/testing#T">testing.T</a> is one doc link.
+<li><p>So is <a href="https://pkg.go.dev/testing#M">testing.M</a>.
+<li><p>So is <a href="https://pkg.go.dev/testing#B">testing.B</a>.
+This is the same list paragraph.
+<p>There is <a href="https://pkg.go.dev/testing#PB">testing.PB</a> in this list item, too!
+</ul>

src/go/doc/comment/testdata/linklist3.txt

@@ -0,0 +1,31 @@
+{"DocLinkBaseURL": "https://pkg.go.dev"}
+-- input --
+Cool things:
+
+  - Foo
+  - [Go]
+  - Bar
+
+[Go]: https://go.dev/
+-- text --
+Cool things:
+
+  - Foo
+  - Go
+  - Bar
+
+[Go]: https://go.dev/
+-- markdown --
+Cool things:
+
+  - Foo
+  - [Go](https://go.dev/)
+  - Bar
+
+-- html --
+<p>Cool things:
+<ul>
+<li>Foo
+<li><a href="https://go.dev/">Go</a>
+<li>Bar
+</ul>

src/go/doc/comment/testdata/linklist4.txt

@@ -0,0 +1,36 @@
+{"DocLinkBaseURL": "https://pkg.go.dev"}
+-- input --
+Cool things:
+
+  - Foo
+  - [Go] is great
+
+    [Go]: https://go.dev/
+  - Bar
+
+-- text --
+Cool things:
+
+  - Foo
+
+  - Go is great
+
+  - Bar
+
+[Go]: https://go.dev/
+-- markdown --
+Cool things:
+
+  - Foo
+
+  - [Go](https://go.dev/) is great
+
+  - Bar
+
+-- html --
+<p>Cool things:
+<ul>
+<li><p>Foo
+<li><p><a href="https://go.dev/">Go</a> is great
+<li><p>Bar
+</ul>