fdo#32059: Fix this once and for all

Fix a regression from 356b2f0e.

This regression was about the setSelection function. We inserted the command with a space
in the right side of the string, but our selection was not counting the " " character.

So, reasign the variable with the space solve this issue.

Change-Id: Ic48f1afaec89c6eefe73d051d3b0eba7edbf557e
Reviewed-on: https://gerrit.libreoffice.org/5688Reviewed-by: Ricardo Montania <ricardo@linuxafundo.com.br>
Reviewed-by: Marcos Souza <marcos.souza.org@gmail.com>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>
Tested-by: Norbert Thiebaud <nthiebaud@gmail.com>

starmath/source/edit.cxx

@@ -790,9 +790,9 @@ void SmEditWindow::InsertCommand(sal_uInt16 nCommand)
 
         // put a space before a new command if not in the beginning of a line
         if (aSelection.nStartPos > 0 && aCurrentFormula[nStartIndex - 1] != ' ')
-            pEditView->InsertText(" " + aText);
-        else
-            pEditView->InsertText(aText);
+            aText = " " + aText;
+
+        pEditView->InsertText(aText);
 
         // Remember start of the selection and move the cursor there afterwards.
         aSelection.nEndPara = aSelection.nStartPara;