readline: crlfDelay and fs streams

[vsemozhetbyt]

• Version: from v6.6.0
• Platform: mostly Windows
• Subsystem: readline

Recently, I've got a complaint that some of my old scripts for a line by line processing of big files add unexpected new lines. The cause seems to be similar to the one described in this OP.

I suggest two variants of precaution:

1. Add a small note to the doc + set crlfDelay to Infinity in our main file stream example. This change is milder, but it is also a bit confusing and makes the fs example look like a workaround or even an abuse of terminal API.

2. Automatically set crlfDelay to Infinity when terminal is false or even completely remove this check from ._normalWrite(). Is there any reason for this option in fs use cases?

Refs: #8109, #13497

[Fishrock123]

I think 2. seems reasonable?

[vsemozhetbyt]

So maybe I shall start with a doc change. If anybody is confident enough to implement the second change, then the doc change can be reverted,