Move start position for elements (#593)

* Update print-to-json.go

* Create ninety-cherries-guess.md

* Update print-to-json.go

Author: natemoo-re

.changeset/ninety-cherries-guess.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/compiler': patch
+---
+
+AST: move `start` position of elements to the first index of their opening tag

internal/printer/print-to-json.go

@@ -143,9 +143,13 @@ func positionAt(p *printer, n *Node, opts t.ParseOptions) ASTPosition {
 	if len(n.Loc) == 2 {
 		s := n.Loc[0]
 		e := n.Loc[1]
-		// `e` marks the start location of the end tag
+		// `s` and `e` mark the start location of the tag name
 		if n.Type == ElementNode {
-			// this adjusts it to be the last index of the end tag
+			if (s.Start != 0) {
+				// this adjusts `s` to be the first index of the element tag
+				s.Start = s.Start - 1
+			}
+			// this adjusts `e` to be the last index of the end tag
 			e.Start = e.Start + len(n.Data) + 1
 		}
 		start := locToPoint(p, s)