Fix overly greedy parsing in raw elements parser

[deej-io]

Hello!

I have been using templ for a project where I am using non-standard HTML elements and I hit a parse error when I used a tag named <scripts>.

In the existing code, if the raw element name is successfully parsed, it immediately attempts to parse the attributes, without checking for whitespace or a closing >.

This means that something like <scripts> would be parsed as a <script> tag with a boolean attribute of s (the last character of the tag name). This would then give a confusing error about mismatched tags as the closing </scripts> tag was actually parsed correctly.

--- FAIL: TestRawElementParserIsNotGreedy (0.00s)
    --- FAIL: TestRawElementParserIsNotGreedy/styles_tag (0.00s)
        raw_test.go:115: unexpected error: <style>: expected end tag not present: line 0, col 8
    --- FAIL: TestRawElementParserIsNotGreedy/scripts_tag (0.00s)
        raw_test.go:115: unexpected error: <script>: expected end tag not present: line 0, col 9

This commit fixes this issue by delegating to the elementNameParser, which checks for white space or a closing >, and then compares the name of the expected raw element.

[a-h]

Thanks for that!