chore: tables in code excerpts should use headers for line numbers

Author: gitstart-sourcegraph

client/branded/src/components/panel/views/__snapshots__/HierarchicalLocationsView.test.tsx.snap

@@ -341,7 +341,7 @@ export const CodeExcerpt: React.FunctionComponent<Props> = ({
                         <tbody>
                             {range(startLine, endLine).map(index => (
                                 <tr key={index}>
-                                    <td className="line" data-line={index + 1} />
+                                    <th className="line" data-line={index + 1} />
                                     {/* create empty space to fill viewport (as if the blob content were already fetched, otherwise we'll overfetch) */}
                                     <td className="code"> </td>
                                 </tr>

client/search-ui/src/components/CodeExcerpt.tsx

@@ -562,7 +562,7 @@ func generatePlainTable(code string) (*HighlightedCode, error) {
 		tr := &html.Node{Type: html.ElementNode, DataAtom: atom.Tr, Data: atom.Tr.String()}
 		table.AppendChild(tr)
 
-		tdLineNumber := &html.Node{Type: html.ElementNode, DataAtom: atom.Td, Data: atom.Td.String()}
+		tdLineNumber := &html.Node{Type: html.ElementNode, DataAtom: atom.Th, Data: atom.Th.String()}
 		tdLineNumber.Attr = append(tdLineNumber.Attr, html.Attribute{Key: "class", Val: "line"})
 		tdLineNumber.Attr = append(tdLineNumber.Attr, html.Attribute{Key: "data-line", Val: fmt.Sprint(row + 1)})
 		tr.AppendChild(tdLineNumber)

cmd/frontend/internal/highlight/highlight.go

@@ -52,8 +52,8 @@ func TestGeneratePlainTable(t *testing.T) {
 line 2
 
 `
-	want := template.HTML(`<table><tr><td class="line" data-line="1"></td><td class="code"><span>line 1</span></td></tr><tr><td class="line" data-line="2"></td><td class="code"><span>line 2</span></td></tr><tr><td class="line" data-line="3"></td><td class="code"><span>
-</span></td></tr><tr><td class="line" data-line="4"></td><td class="code"><span>
+	want := template.HTML(`<table><tr><th class="line" data-line="1"></th><td class="code"><span>line 1</span></td></tr><tr><th class="line" data-line="2"></th><td class="code"><span>line 2</span></td></tr><tr><th class="line" data-line="3"></th><td class="code"><span>
+</span></td></tr><tr><th class="line" data-line="4"></th><td class="code"><span>
 </span></td></tr></table>`)
 	response, err := generatePlainTable(input)
 	if err != nil {
@@ -71,8 +71,8 @@ func TestGeneratePlainTableSecurity(t *testing.T) {
 <script>alert("line 2")</script>
 
 `
-	want := template.HTML(`<table><tr><td class="line" data-line="1"></td><td class="code"><span>&lt;strong&gt;line 1&lt;/strong&gt;</span></td></tr><tr><td class="line" data-line="2"></td><td class="code"><span>&lt;script&gt;alert(&#34;line 2&#34;)&lt;/script&gt;</span></td></tr><tr><td class="line" data-line="3"></td><td class="code"><span>
-</span></td></tr><tr><td class="line" data-line="4"></td><td class="code"><span>
+	want := template.HTML(`<table><tr><th class="line" data-line="1"></th><td class="code"><span>&lt;strong&gt;line 1&lt;/strong&gt;</span></td></tr><tr><th class="line" data-line="2"></th><td class="code"><span>&lt;script&gt;alert(&#34;line 2&#34;)&lt;/script&gt;</span></td></tr><tr><th class="line" data-line="3"></th><td class="code"><span>
+</span></td></tr><tr><th class="line" data-line="4"></th><td class="code"><span>
 </span></td></tr></table>`)
 	response, err := generatePlainTable(input)
 	if err != nil {

cmd/frontend/internal/highlight/highlight_test.go

@@ -228,7 +228,7 @@ func newHtmlRow(row int32, includeLineNumbers bool) (htmlRow, htmlCode *html.Nod
 	tr := &html.Node{Type: html.ElementNode, DataAtom: atom.Tr, Data: atom.Tr.String()}
 
 	if includeLineNumbers {
-		tdLineNumber := &html.Node{Type: html.ElementNode, DataAtom: atom.Td, Data: atom.Td.String()}
+		tdLineNumber := &html.Node{Type: html.ElementNode, DataAtom: atom.Th, Data: atom.Th.String()}
 		tdLineNumber.Attr = append(tdLineNumber.Attr, html.Attribute{Key: "class", Val: "line"})
 		tdLineNumber.Attr = append(tdLineNumber.Attr, html.Attribute{Key: "data-line", Val: fmt.Sprint(row + 1)})
 		tr.AppendChild(tdLineNumber)