fix(toml): Don't error on infostrings with trailing whitespace

Author: epage

src/cargo/util/toml/embedded.rs

@@ -245,8 +245,9 @@ fn split_source(input: &str) -> CargoResult<Source<'_>> {
         _ => source.content.split_at(fence_end),
     };
     let (info, content) = rest.split_once("\n").unwrap_or((rest, ""));
+    let info = info.trim_end();
     if !info.is_empty() {
-        source.info = Some(info.trim_end());
+        source.info = Some(info);
     }
     source.content = content;
 
@@ -411,7 +412,7 @@ content: "fn main() {}\n"
                 "#!/usr/bin/env cargo\r\n---\r\n[dependencies]\r\ntime=\"0.1.25\"\r\n---\r\nfn main() {}",
             str![[r##"
 shebang: "#!/usr/bin/env cargo\r\n"
-info: ""
+info: None
 frontmatter: "[dependencies]\r\ntime=\"0.1.25\"\r\n"
 content: "fn main() {}"