fix: CRLF newline handling and error span rendering

[metalurgical]

Previously, CRLF was treated as two newlines, causing incorrect line numbers, extra blank lines, and misaligned spans on Windows.

• treat CRLF as a single newline
• use consistent newline handling for line/column calculation and display
• fix trailing space rendering on empty lines
• preserve UTF-16 column alignment and span rendering

[metalurgical]

resolves #261
closes #261

[KyrylR]

#257 was merged, could you rebase pls

Also, have to ask you to narrow down the changes to CRLF only due to the reason that the lexer is limited to the LF/CRLF/CR (\n, \r\n, \r), though I do not see a reason to support CR, as it seems a legacy thing

[apoelstra]

ab4848a needs rebase

[metalurgical]

#257 was merged, could you rebase pls

Also, have to ask you to narrow down the changes to CRLF only due to the reason that the lexer is limited to the LF/CRLF/CR (\n, \r\n, \r), though I do not see a reason to support CR, as it seems a legacy thing

Has been narrowed to an explicit check instead of via is_newline().

[KyrylR]

Need to take a deeper look, there could be an issue with lexer that still uses .padded(), and Chumsky treats \r as whitespace there, so lone-\r input is still accepted

[metalurgical]

Need to take a deeper look, there could be an issue with lexer that still uses .padded(), and Chumsky treats \r as whitespace there, so lone-\r input is still accepted

I suspected CR still needed to be handled. So in this instance should it be erased or treated as a newline?