Previously the lexer would break out of consuming a text token if it contains
a `<` character. Then if the next characters did not indicate an HTML syntax
item, such as a tag or comment, then it would start a new text token. These
consecutive text tokens are then merged into each other in a post tokenization
step.
In the commit before this, interpolation no longer leaks across text tokens.
The approach given above to handling `<` characters that appear in text is
no longer adequate. This change ensures that the lexer only breaks out of
a text token if the next characters indicate a valid HTML tag, comment,
CDATA etc.
PR Close#42605