In Helix, selecting a line with `x` creates a selection from column 0 of
the current row to column 0 of the next row. The default
`InsertEndOfLine` uses the selection head (which is on the next row) to
find the line end, placing the cursor on the wrong line. 

This commit introduces a new `HelixInsertEndOfLine`, mapped by default
to `shift-a` when Helix mode is enabled, that moves left from the head
first to land on the correct line.

Release Notes:

- Fixed `shift-a` in Helix select mode placing the cursor on the wrong
line after selecting with `x`

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Co-authored-by: SkandaBhat <9384046+SkandaBhat@users.noreply.github.com>
Co-authored-by: dino <dinojoaocosta@gmail.com>