RFR: 8335547: Support multi-line prompt text for TextArea [v4]

[Ziad El Midaoui]

On Fri, 28 Mar 2025 20:22:39 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Option 1 is intentionally the status quo, and matches what Swing's JComponent does, although @mstr2 is right that this isn't documented. An RFE to treat `\r` or `\r\n` as a newline could be considered in the future. We wouldn't do that as part of this PR.
>> 
>> So for _this_ PR, the question is what characters should be elided for the prompt text of a `TextField` so that multiple lines as a single line? Limiting this to stripping `\n` is sufficient given the current implementation, unless and until something else changes. Also, it matches what the existing implementation tries to do when it modifies the actual property value.
>
> One thing I am curious about: I don't see a similar stripping of newlines in the text itself for TextField, and yet it does render the whole string as if the newline had been stripped. Do you know why we need to strip it from promptTextProperty explicitly and not from textProperty?

@kevinrushforth 
This is due to `TextFieldContent::insert` we have a filterInput and the second parameter to strip newlines is set to true in the textField class.
`filterInput(String txt, boolean stripNewlines, boolean stripTabs)`
For `TextAreaContent::insert` the parameter is set to false to allow newlines.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1716#discussion_r2031472786