Add support for trimming whitespace around string, text

This commit introduces trimming initial and final whitespace around the
whole string or text, or around line endings inside that string or text.

*   Add `register_resolver_before`, to run resolvers earlier than others,
    used for labels
*   Add resolver to merge `data` events, which are the most frequent token
    that occurs, and can happen adjacently.
    In `micromark-js` this sped up parsing a lot
*   Fix a bug where a virtual space was not seen as an okay event
*   Refactor to enable all turned off whitespace tests

1 files changed, 12 insertions, 5 deletions

diff --git a/src/content/string.rs b/src/content/string.rs
index 53e88b1..cc8ee53 100644
--- a/src/content/string.rs
+++ b/src/content/string.rs
@@ -14,13 +14,16 @@
 
 use crate::construct::{
     character_escape::start as character_escape, character_reference::start as character_reference,
-    partial_data::start as data,
+    partial_data::start as data, partial_whitespace::whitespace,
 };
 use crate::tokenizer::{Code, State, StateFnResult, Tokenizer};
 
-const MARKERS: [Code; 2] = [
-    Code::Char('&'),  // `character_reference`
-    Code::Char('\\'), // `character_escape`
+const MARKERS: [Code; 5] = [
+    Code::VirtualSpace, // `whitespace`
+    Code::Char('\t'),   // `whitespace`
+    Code::Char(' '),    // `whitespace`
+    Code::Char('&'),    // `character_reference`
+    Code::Char('\\'),   // `character_escape`
 ];
 
 /// Before string.
@@ -34,7 +37,11 @@ pub fn start(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult {
     match code {
         Code::None => (State::Ok, None),
         _ => tokenizer.attempt_n(
-            vec![Box::new(character_reference), Box::new(character_escape)],
+            vec![
+                Box::new(character_reference),
+                Box::new(character_escape),
+                Box::new(whitespace),
+            ],
             |ok| Box::new(if ok { start } else { before_data }),
         )(tokenizer, code),
     }