Trim trailing whitespace in pre blocks in Markdown

src/browser/markdown.zig

@@ -36,6 +36,7 @@ const State = struct {
     list_depth: usize = 0,
     list_stack: [32]ListState = undefined,
     in_pre: bool = false,
+    pre_node: ?*Node = null,
     in_code: bool = false,
     in_blockquote: bool = false,
     in_table: bool = false,
@@ -63,7 +64,15 @@ const State = struct {
         },
         .cdata => |cd| {
             if (node.is(Node.CData.Text)) |_| {
-                    try renderText(cd.getData(), state, writer);
+                var text = cd.getData();
+                if (state.in_pre) {
+                    if (state.pre_node) |pre| {
+                        if (node.parentNode() == pre and node.nextSibling() == null) {
+                            text = std.mem.trimRight(u8, text, " \t\r\n");
+                        }
+                    }
+                }
+                try renderText(text, state, writer);
             }
         },
         else => {}, // Ignore other node types
@@ -163,13 +172,15 @@ const State = struct {
             // Add spacing
             try writer.writeByte(' ');
         },
-            .blockquote => {            try writer.writeAll("> ");
+        .blockquote => {
+            try writer.writeAll("> ");
             state.in_blockquote = true;
             state.last_char_was_newline = false;
         },
         .pre => {
             try writer.writeAll("```\n");
             state.in_pre = true;
+            state.pre_node = el.asNode();
             state.last_char_was_newline = true;
         },
         .code => {
@@ -259,6 +270,7 @@ const State = struct {
             }
             try writer.writeAll("```\n");
             state.in_pre = false;
+            state.pre_node = null;
             state.last_char_was_newline = true;
         },
         .code => {