improve parse_block perf slightly (#262)

Author: joshuadavidthomas

crates/djls-templates/src/parser.rs

@@ -17,8 +17,8 @@ impl Parser {
     }
 
     pub fn parse(&mut self) -> (Vec<Node>, Vec<ParseError>) {
-        let mut nodelist = Vec::new();
-        let mut errors = Vec::new();
+        let mut nodelist = Vec::with_capacity(self.tokens.len() / 2);
+        let mut errors = Vec::with_capacity(4);
 
         while !self.is_at_end() {
             match self.next_node() {
@@ -85,11 +85,15 @@ impl Parser {
             });
         };
 
-        let mut parts = content_ref.split_whitespace();
+        let mut parts = content_ref.split_ascii_whitespace();
 
         let name = parts.next().ok_or(ParseError::EmptyTag)?.to_string();
 
-        let bits = parts.map(std::string::ToString::to_string).collect();
+        let mut bits = Vec::with_capacity(parts.clone().count());
+        for part in parts {
+            bits.push(part.to_owned());
+        }
+
         let span = token.content_span_or_fallback();
 
         Ok(Node::Tag { name, bits, span })