improve parsing of errors

[zenwork]

Adding, Removing, or Changing

Adding

Type of Modification

better handling of lexing errors

What are you trying to modify

See discussion in #108

Parsing of errors should "break" the lexing and parsing and syntax checking better. This is a problem in many places.

Alternatives

No response

[zenwork]

Although the error handling is much better since completing #94 , it is not clear how the plugin should support new custom tags such as in this example:

import vento from './vento/mod.ts'

const env = vento()
env.tags.push((env, token, output) => {
	if(token[1] != '/s') return
	return `${output} += '(sarcasm)'`
})

const output = await env.runString(`
	 Using /s is so in right now {{ /s }}
`)

console.log(output)