Fix horizontal relocation (scrolling) not respecting selections

[masmu]

Currently there is no logic to handle horizontal scrolling when text is selected. The current code only takes the cursor position into account. This only affects buffers where the softwrap option is disabled.

How to reproduce:

PLUGIN_VERSION = "2.0.0"
PLUGIN_NAME = "bug_horizontal_relocate_doesnt_respect_selections"

local micro = import("micro")
local buffer = import("micro/buffer")
local config = import("micro/config")
local util = import("micro/util")

local TEST_STRING1 = [[
//        1         2         3         4         5         6         7         8         9
//23456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
    scrollbarWidth := 0
	scrollbarWidth := 0
	if w.Buf.Settings["scrollbar"].(bool) && w.Buf.LinesNum() > w.Height && w.Width > 0 {
		scrollbarWidth = 1
	}]]

local TEST_STRING2 = [[
//        1         2         3         4         5         6         7         8         9
//23456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
// ThisIsAVeryLongLineSoLongActuallyItsNotGonnaFitIntoOneBufSplit
	// >>> ThisIsAVeryLongLineSoLongActuallyItsNotGonnaFitIntoOneBufSplit]]

function postinit()
    local bp = micro.CurPane()
    if bp.Buf:Size() > 0 then
        return
    end
    bp.Buf.settings["softwrap"] = false
    bp.Buf.settings["tabsize"] = 4
    micro.Log("tabsize", bp.Buf.settings["tabsize"])
    micro.Log("softwrap", bp.Buf.settings["softwrap"])
    testCase1a()
    -- testCase2()
end

function resizePane(bp, size)
    -- bp:ResizePane(size, true)
    bp:ResizePane(size)
end

function testCase1a()
    local bp = micro.CurPane()
    local cursor = bp.Buf:GetActiveCursor()
    bp.Buf:Insert(-cursor.Loc, TEST_STRING1)

    local unusedBuf, err = buffer.NewBufferFromFile("")
    local unusedBp = bp:VSplitIndex(unusedBuf, true)
    resizePane(bp, 60)

    local tab = bp:Tab()
    tab:SetActive(bp:ID() - 1)

    -- select "Width"
    local loc = buffer.Loc(10, 3)
    cursor:GotoLoc(loc)
    bp:SelectSubWordRight()
end

function testCase2()
    local bp = micro.CurPane()
    local cursor = bp.Buf:GetActiveCursor()
    bp.Buf:Insert(-cursor.Loc, TEST_STRING2)

    local unusedBuf, err = buffer.NewBufferFromFile("")
    local unusedBp = bp:VSplitIndex(unusedBuf, true)
    resizePane(bp, 60)

    local tab = bp:Tab()
    tab:SetActive(bp:ID() - 1)

    -- select "ThisIsAVeryLongLineSoLongActuallyItsNotGonnaFitIntoOneBufSplit"
    local loc = buffer.Loc(3, 2)
    cursor:GotoLoc(loc)
    bp:SelectWordRight()
end

function onTriggerBug(bp)
    micro.Log("onTriggerBug")
    local bp = micro.CurPane()
    local cursor = bp.Buf:GetActiveCursor()
    if cursor:HasSelection() == false then
        return false
    end
    local selectedText = util.String(cursor:GetSelection())
    bp.Buf.LastSearch = selectedText
    bp:FindNext()
end

Bind onTriggerBug to see the effect.

Actual behavior:
You cannot see the selected subword Width every time you trigger onTriggerBug.

Expectation:
The selected text should be visible at all times.