Show BUG comments in godoc:

ast.go:
- rename Comments -> CommentGroup (less confusion)
- change all comments/docs to be *CommentGroup

filter.go:
- do not remove unassociated comments from program as part
  of export filtering (they are needed by doc.go for BUG comments)

scanner.go:
- exclude '\n' from //-style comments

parser.go:
- rewrote collection of comments: now all collected comments
  are *ast.CommentGroups
- clarified distinction between leading and trailing comments
- fixed a bug in comment collection (parseGenDecl);
  corresponding test case is in printer/testdata
- extra documentation

doc.go:
- collect BUG comments
- corresponding fix for parser bug in comment collection

comment.go:
- simplified regex

printer.go:
- adjust comment printing to new representation

printer_test.go, testdata/*:
- enable printing of doc comments
- extended tests

package.html, package.txt:
- added Bugs section

gofmt:
- enable printing of doc comments

R=rsc
DELTA=339  (126 added, 38 deleted, 175 changed)
OCL=31403
CL=31416

2 files changed, 15 insertions, 0 deletions

diff --git a/lib/godoc/package.html b/lib/godoc/package.html
index 8d430743c4..0f1b0457d8 100644
--- a/lib/godoc/package.html
+++ b/lib/godoc/package.html
@@ -51,4 +51,11 @@
 			{.end}
 		{.end}
 	{.end}
+	{.section Bugs}
+		<hr />
+		<h2>Bugs</h2>
+		{.repeated section @}
+		{@|html-comment}
+		{.end}
+	{.end}
 {.end}
diff --git a/lib/godoc/package.txt b/lib/godoc/package.txt
index 542c2c460e..0dde78c6cf 100644
--- a/lib/godoc/package.txt
+++ b/lib/godoc/package.txt
@@ -58,4 +58,12 @@ TYPES
 {.end}
 {.end}
 {.end}
+{.section Bugs}
+
+BUGS
+
+{.repeated section @}
+{@}
+{.end}
+{.end}
 {.end}