Fix extra line breaks being inserted before lists

Sources/HTMLStreamer/AttributedStringConverter.swift

@@ -135,7 +135,7 @@ public struct AttributedStringConverter<Callbacks: HTMLConversionCallbacks> {
             finishRun()
             styleStack.append(.unorderedList)
         case "li":
-            if str.length != 0 || !currentRun.isEmpty {
+            if !currentRun.isEmpty {
                 currentRun.append("\n")
             }
             let marker: String

Tests/HTMLStreamerTests/AttributedStringConverterTests.swift

@@ -319,4 +319,19 @@ final class AttributedStringConverterTests: XCTestCase {
         XCTAssertEqual(convert("<p></p><blockquote><span>inside<br>quote</span></blockquote><span>after</span><p></p>"), result)
     }
     
+    func testParagraphFollowedByList() {
+        let result = NSMutableAttributedString()
+        result.append(NSAttributedString(string: "a\n\n", attributes: [
+            .font: font,
+            .paragraphStyle: NSParagraphStyle.default,
+            .foregroundColor: color,
+        ]))
+        result.append(NSAttributedString(string: "\t1.\tb", attributes: [
+            .font: font,
+            .paragraphStyle: listParagraphStyle,
+            .foregroundColor: color,
+        ]))
+        XCTAssertEqual(convert("<p>a</p><ol><li>b</li></ol>"), result)
+    }
+    
 }