fix: don't error if no open brace is found on control flow expressions

[joerdav]

fixes #141

[joerdav]

@a-h Is this how you would expect this to have been fixed?

[a-h]

Very close. I was thinking about attempting to search for a greater number of symbols before templ complains about a malformed for or if

For example. The for statement must be constructed in a number of ways.

package main

import "fmt"

func main() {
	var x int
	for ; x < 10; x++ {
		print(x)
	}
	fmt.Println()
	for y := 0; y < 10; y++ {
		print(y)
	}
	for {
		break
	}
	fmt.Println()
	var y int
	for y = 0; y < 10; y++ {
		print(y)
	}
}

https://go.dev/play/p/RjaP5Hj5HkV

I was thinking of still complaining about the for statement not being closed if there's a semicolon in the line. However, that would simply reduce the times that the spurious error occurs.

My concern was developers accidentally turning a malformed for loop into printing for x := 0; x < checkSomething(); x ++ to the HTML.

So I was thinking about ways to reduce the number of spurious errors while providing some protection against forgetting to close a for loop start expression.

[joerdav]

Makes sense. It's finding that line between errors that stop someone from writing certain things in an element and allowing broken for loops to be written.

I guess where it gets harder is if and switch statements, they are unlikely to contain any discerning character between the keyword and the open-brace.