Fix Clippy warnings (#886)

This addresses the following Clippy warnings:

* clippy::option_and_then_some
* clippy::useless_format

components/front_matter/src/page.rs

@@ -87,11 +87,11 @@ impl PageFrontMatter {
     pub fn date_to_datetime(&mut self) {
         self.datetime = if let Some(ref d) = self.date {
             if d.contains('T') {
-                DateTime::parse_from_rfc3339(&d).ok().and_then(|s| Some(s.naive_local()))
+                DateTime::parse_from_rfc3339(&d).ok().map(|s| s.naive_local())
             } else {
                 NaiveDate::parse_from_str(&d, "%Y-%m-%d")
                     .ok()
-                    .and_then(|s| Some(s.and_hms(0, 0, 0)))
+                    .map(|s| s.and_hms(0, 0, 0))
             }
         } else {
             None

components/library/src/pagination/mod.rs

@@ -190,7 +190,7 @@ impl<'a> Paginator<'a> {
         }
         paginator.insert("number_pagers", to_value(&self.pagers.len()).unwrap());
         let base_url = if self.paginate_path.is_empty() {
-            format!("{}", self.permalink)
+            self.permalink.to_string()
         } else {
             format!("{}{}/", self.permalink, self.paginate_path)
         };