Inconsistent behaviors of trailing line breaks in a literal string

[na4zagin3]

Current behavior

If a literal string has trailing spaces (U+0020), a `<string>` style literal removes all the trailing spaces while a `<string>`# retains all.

On the other hand, if a literal string has trailing line breaks a `<string>` style literal removes only one trailing line breaks and a `<string>`# removes up to two of them. Neither removes spaces followed by the trailing line breaks.

This code

let display-message-with-boundaries str = display-message (`@` ^ str ^ `@`) 
let _ = display-message-with-boundaries ```3LF+# 


```#
let _ = display-message-with-boundaries ```2LF+# 

```#
let _ = display-message-with-boundaries ```1LF+# 
```#
let _ = display-message-with-boundaries ```3LF 


```
let _ = display-message-with-boundaries ```2LF 

```

let _ = display-message-with-boundaries ```1LF 
```

produces the following result

@3LF+# 

@
@2LF+# 
@
@1LF+# @
@3LF 
@
@2LF @
@1LF @

I summarize the result in the following table where ⏎ represents a line break character (U+000A) and ␣ a space (U+0020).

Literal	Interpreted
`a␣⏎`#	a␣
`a␣⏎⏎`#	a␣⏎
`a␣⏎⏎⏎`#	a␣⏎⏎
`a␣⏎`	a␣
`a␣⏎⏎`	a␣
`a␣⏎⏎⏎`	a␣⏎
`a␣⏎⏎⏎⏎`	a␣⏎⏎

Expected behaviors

I would expect one of the following options:

• Both trailing line breaks and spaces are equally treated. I.e., `string`# style literal preserves any trailing line breaks or spaces while `string`# style trims all the trailing line breaks and spaces.

  For example, `a␣⏎␣⏎`# and `a␣⏎␣⏎` will represent a␣⏎␣⏎ and a, respectively.

• When there are trailing line breaks following spaces, the spaces won't be removed.

  • `string`# style literal preserves all the trailing line breaks while `string`# style trims all the trailing line breaks.

  For example, `a⏎⏎⏎`# and `a⏎⏎⏎` will represent a⏎⏎⏎ and a, respectively.

  • `string`# style literal preserves up to one trailing line break while `string`# style trims all the trailing line breaks.

  For example, `a⏎⏎⏎`# and `a⏎⏎⏎` will represent a⏎⏎ and a, respectively.

Original comment: https://satysfi.slack.com/archives/CTGUT75FZ/p1584115832024200