Fix first line background.

Added a comment if the background in desired in the future.

src/gui/filesystem.rs

@@ -10,9 +10,7 @@ use std::fs;
 use std::path::Path;
 use syntect::easy::HighlightLines;
 use syntect::highlighting::ThemeSet;
-use syntect::html::{
-    IncludeBackground, append_highlighted_html_for_styled_line, start_highlighted_html_snippet,
-};
+use syntect::html::{IncludeBackground, append_highlighted_html_for_styled_line};
 use syntect::parsing::SyntaxSet;
 use syntect::util::LinesWithEndings;
 
@@ -99,7 +97,8 @@ impl qobject::FileSystem {
                 )
                 .unwrap_or_else(|| ss.find_syntax_plain_text());
             let mut highlighter = HighlightLines::new(lang, theme);
-            let (mut output, _bg) = start_highlighted_html_snippet(theme);
+            // If you care about the background, see `start_highlighted_html_snippet(theme);`.
+            let mut output = String::from("<pre>\n");
             for line in LinesWithEndings::from(lines.as_str()) {
                 let regions = highlighter
                     .highlight_line(line, &ss)