Improve Remove Consecutive Duplicate Lines command

[ArkadiuszMichalski]

The following changes for the Remove Consecutive Duplicate Lines command can be done to improve it:

1. Directly checking two consecutive duplicate lines without checking all the data (similar as for Remove Empty Lines)
2. Add automatically expand selections for partially selected lines. This is how Remove Duplicate Lines works, and it's worth making both consistent.

Some problems with different EOLs #13474 (comment). General discussion about this: #12780.

Other problem #5538.

Notepad++ v8.4.7   (32-bit)
Build time : Nov 21 2022 - 02:30:12
Path : D:\_test\NPPClean\notepad++.exe
Command Line : -multiInst
Admin mode : OFF
Local Conf mode : ON
Cloud Config : OFF
OS Name : Windows 11 (64-bit) 
OS Version : 21H2
OS Build : 22000.1219
Current ANSI codepage : 1250
Plugins : 
    mimeTools (2.8)
    NppConverter (4.4)
    NppExport (0.4)