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, 16 insertions, 19 deletions

diff --git a/tests/heading_setext.rs b/tests/heading_setext.rs
index ecf22a8..e7ee9ff 100644
--- a/tests/heading_setext.rs
+++ b/tests/heading_setext.rs
@@ -24,7 +24,7 @@ fn heading_setext() {
     //     "should support line endings in setext headings"
     // );
 
-    // To do: attention, trim.
+    // To do: attention.
     // assert_eq!(
     //     micromark("  Foo *bar\nbaz*\t\n===="),
     //     "<h1>Foo <em>bar\nbaz</em></h1>",
@@ -85,19 +85,17 @@ fn heading_setext() {
         "should support whitespace before underline"
     );
 
-    // To do: trim paragraphs.
-    // assert_eq!(
-    //     micromark("Foo\n    ="),
-    //     "<p>Foo\n=</p>",
-    //     "should not support too much whitespace before underline (1)"
-    // );
+    assert_eq!(
+        micromark("Foo\n    ="),
+        "<p>Foo\n=</p>",
+        "should not support too much whitespace before underline (1)"
+    );
 
-    // To do: trim paragraphs.
-    // assert_eq!(
-    //     micromark("Foo\n\t="),
-    //     "<p>Foo\n=</p>",
-    //     "should not support too much whitespace before underline (2)"
-    // );
+    assert_eq!(
+        micromark("Foo\n\t="),
+        "<p>Foo\n=</p>",
+        "should not support too much whitespace before underline (2)"
+    );
 
     assert_eq!(
         micromark("Foo\n= ="),
@@ -111,12 +109,11 @@ fn heading_setext() {
         "should not support whitespace in the underline (2)"
     );
 
-    // To do: trim setext.
-    // assert_eq!(
-    //     micromark("Foo  \n-----"),
-    //     "<h2>Foo</h2>",
-    //     "should not support a hard break w/ spaces at the end"
-    // );
+    assert_eq!(
+        micromark("Foo  \n-----"),
+        "<h2>Foo</h2>",
+        "should not support a hard break w/ spaces at the end"
+    );
 
     assert_eq!(
         micromark("Foo\\\n-----"),