Update comrak

This removes 4 dependencies, including two duplicate copies of `syn` and
`quote`.

```
$ cargo update -p comrak
    Updating crates.io index
    Updating comrak v0.3.1 -> v0.8.0
    Removing pest v1.0.6
    Removing pest_derive v1.0.8
    Removing quote v0.3.15
    Removing syn v0.11.11
    Removing synom v0.11.3
      Adding twoway v0.2.1
      Adding unchecked-index v0.2.2
    Removing unicode-xid v0.0.4
```

- Remove `safe = true`

This was made the default in 0.4.0. The field is now called `unsafe_`.

https://github.com/kivikakk/comrak/blob/master/changelog.txt#L63

Author: jyn514

Cargo.lock

@@ -25,7 +25,7 @@ url = { version = "2.1.1", features = ["serde"] }
 badge = { path = "src/web/badge" }
 backtrace = "0.3"
 failure = { version = "0.1.3", features = ["backtrace"] }
-comrak = { version = "0.3", default-features = false }
+comrak = { version = "0.8", default-features = false }
 toml = "0.5"
 kuchiki = "0.8"
 schemamama = "0.3"

Cargo.toml

@@ -369,17 +369,18 @@ fn match_version(conn: &Connection, name: &str, version: Option<&str>) -> Option
 
 /// Wrapper around the Markdown parser and renderer to render markdown
 fn render_markdown(text: &str) -> String {
-    use comrak::{markdown_to_html, ComrakOptions};
-
-    let options = {
-        let mut options = ComrakOptions::default();
-        options.safe = true;
-        options.ext_superscript = true;
-        options.ext_table = true;
-        options.ext_autolink = true;
-        options.ext_tasklist = true;
-        options.ext_strikethrough = true;
-        options
+    use comrak::{markdown_to_html, ComrakExtensionOptions, ComrakOptions};
+
+    let options = ComrakOptions {
+        extension: ComrakExtensionOptions {
+            superscript: true,
+            table: true,
+            autolink: true,
+            tasklist: true,
+            strikethrough: true,
+            ..ComrakExtensionOptions::default()
+        },
+        ..ComrakOptions::default()
     };
 
     markdown_to_html(text, &options)