chore: Update module version to 7.8.9

Merge pull request #1591 from pbossman/master

Resolve worksheet ArgumentCompleter Fixes:#1590

Merge pull request #1522 from kyllath/master

Add missing parameter aliases to align with caller/callee

Merge pull request #1465 from dfinke/Extend-Get-Excel-File-Summary

Add Get-ExcelFileSchema

Merge pull request #1341 from dfinke/DoNotShowValues-for-Conditional

Add -ShowOnlyIcon to New-ConditionalFormattingIconSet. Base on https:…

Merge pull request #1305 from thkn-hofa/master

TotalSettings improvements

Add Sheet visibility property

update change log

bump version

Merge pull request #1206 from dfinke/Investigate-underlinetype-not-be…

…ing-set

Fix -UnderLineType parameter is ignored in Set-ExcelColumn #1204