Start of flat text element, not handling more complex types like bold and link.

src/parser/text_element_parser.rs

@@ -25,6 +25,14 @@ fn flat_text_element<'s, 'r>(
     i: &'s str,
     context: &'r mut NomContext,
 ) -> Res<&'s str, TextElement<'s>> {
-    // not(&mut context.fail_matcher)(i)?;
-    todo!()
+    context.not_matching_fail(i)?;
+
+    alt((
+        map(span, TextElement::Span),
+        map(symbol("*"), TextElement::Symbol),
+        map(symbol("["), TextElement::Symbol),
+        map(symbol("]"), TextElement::Symbol),
+        map(space, TextElement::Space),
+        map(line_break, TextElement::LineBreak),
+    ))(i)
 }