Update esql-syntax.md - escapechar and quotes.

[mjmbischoff]

I think we need to reword this bit as we don't actually say things like \ is the escape character - which I'm not too well equipped for.

but the \\" is wrong and should be \" so vs escaping escape char and then quote as this fails:

POST _query?format=txt
{
  "query":"""
    ROW a = 1
    | EVAL b = "\\""
"""
}

vs:

POST _query?format=txt
{
  "query":"""
    ROW a = 1
    | EVAL b = "\""
"""
}

[elasticsearchmachine]

Pinging @elastic/core-docs (Team:Docs)

[elasticsearchmachine]

@mjmbischoff please enable the option "Allow edits and access to secrets by maintainers" on your PR. For more information, see the documentation.

[github-actions]

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• docs/reference/query-languages/esql/esql-syntax.md

[leemthompo]

Thanks @mjmbischoff —This change looks correct to me but because escape characters is kinda a can of worms in ESQL, just want to make sure get technical approve from devs :)

[luigidellaquila]

That looks good to me, \\" is incorrect in all cases.

I think the confusion came from the fact that we can escape the string in the query

ROW a = "foo\"bar"

but we can also escape the query itself:

POST _query
{
    "query": "ROW a = \"foo\\\"bar\""
}

and it becomes three escapes in this case.

Let alone all the all the combinations of triple quotes in the JSON payload and in ES|QL strings.

I still haven't found a way to explain all the cases in a way that is clear enough for the end user, so let's stick to this for now.

[elasticsearchmachine]

💚 Backport successful

Status	Branch	Result
✅	9.0
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