Fix String typos. Fix missing space merge-multiple column names

ImportExcel.psm1

@@ -5,7 +5,7 @@ if (-not $Strings) {
     Import-LocalizedData  -UICulture "en" -BindingVariable Strings -FileName Strings -ErrorAction Ignore
 }
 try { [void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") }
-catch { Write-Warning -Message $Strings.SystemDrawingAvaialable }
+catch { Write-Warning -Message $Strings.SystemDrawingAvailable }
 
 foreach ($directory in @('Private', 'Public','Charting','InferData','Pivot')) {
     Get-ChildItem -Path "$PSScriptRoot\$directory\*.ps1" | ForEach-Object {. $_.FullName}

Public/Merge-MultipleSheets.ps1

@@ -89,7 +89,7 @@ function Merge-MultipleSheets {
          if ($filesToProcess.Count -ge 2) {
                $refPrefix       = (Split-Path -Path $filestoProcess[0] -Leaf) -replace "\.xlsx$"," "
          }
-         else {$refPrefix       = $WorksheetName[0] }
+         else {$refPrefix       = $WorksheetName[0] + " "}
          Write-Progress -Activity "Merging sheets" -CurrentOperation "applying formatting to sheet '$OutputSheetName' in $OutputFile"
          #Find the column headings which are in the form "diffFile  is"; which will hold 'Same', 'Added' or 'Changed'
          foreach ($cell in $sheet.Cells[($sheet.Dimension.Address -replace "\d+$","1")].Where({$_.value -match "\sIS$"}) ) {

en/Strings.psd1

@@ -1,5 +1,5 @@
 ConvertFrom-StringData @'
-SystemDrawingAvaialable=System.Drawing could not be loaded. Color and font look-ups may not be available.
+SystemDrawingAvailable=System.Drawing could not be loaded. Color and font look-ups may not be available.
 PS5NeededForPlot=PowerShell 5 is required for plot.ps1
-ModuleReadyExceptPlot=The ImportExcel moudle is ready, except for that functionality
+ModuleReadyExceptPlot=The ImportExcel module is ready, except for that functionality
 '@