Fix class/attribute mixup bug

There's a bug in the current version of GSP where an element like this:

    p .class attribute="value" {-}

would be transpiled as this:

    <p class="value" attribute="value"></p>

The `classes` slice in `func printAttrs` (`formatter.go`, line 50) was
the cause. I fixed it by making a deep copy of the `attrs` slice. I'm not
a Go programmer, there might be a nicer way to make a deep copy of a slice.
But it does, indeed, work.

P.S. thanks for making this, writing HTML by hand is now slightly less
painful!

1 files changed, 4 insertions, 1 deletions

diff --git a/formatter/formatter.go b/formatter/formatter.go
index 6249c0a..7ac41a6 100644
--- a/formatter/formatter.go
+++ b/formatter/formatter.go
@@ -48,14 +48,17 @@ func PrintAst(ast parser.AstNode) {
 }
 
 func printAttrs(attrs []parser.Attr) {
-	classes := attrs
+	classes := make([]parser.Attr, len(attrs), cap(attrs))
+	copy(classes, attrs)
 	classes = slices.DeleteFunc(classes, func(a parser.Attr) bool {
 		return a.Key != "class"
 	})
+
 	attrs = slices.DeleteFunc(attrs, func(a parser.Attr) bool {
 		return a.Key == "class"
 	})
 
+
 	if len(classes) > 0 {
 		fmt.Print(" class=\"")
 		for i, a := range classes {