Fix various typos in source documentation and comments (cont.)

Found via `codespell`

sources/undocommand/addelementtextcommand.cpp

@@ -441,8 +441,8 @@ void AlignmentTextsGroupCommand::undo()
 	if(m_group)
 	{
 		m_group.data()->setAlignment(m_previous_alignment);
-		//The alignment befor this command was free, then we must
-		//to restor the pos of each texts
+		//The alignment before this command was free, then we must
+		//to restore the pos of each texts
 		if(!m_texts_pos.isEmpty())
 		{
 			for(DynamicElementTextItem *deti : m_group.data()->texts())

sources/undocommand/deleteqgraphicsitemcommand.cpp

@@ -31,7 +31,7 @@
 
 /**
 	@brief DeleteQGraphicsItemCommand::DeleteQGraphicsItemCommand
-	@param diagram : deigram where this undo work
+	@param diagram : diagram where this undo work
 	@param content : content to remove
 	@param parent : parent undo
 */
@@ -53,8 +53,8 @@ DeleteQGraphicsItemCommand::DeleteQGraphicsItemCommand(
 
 	}
 
-		//When remove a deti we must to know his parent item, for re-add deti as child of the parent
-		//when undo this command
+		//When removing a deti we must know its parent item, for re-adding deti as child of the parent
+		//when undoing this command
 	for(DynamicElementTextItem *deti : m_removed_contents.m_element_texts)
 	{
 		if(deti->parentGroup())

sources/undocommand/linkelementcommand.cpp

@@ -259,12 +259,12 @@ void LinkElementCommand::setUpNewLink(
 /**
 	@brief LinkElementCommand::makeLink
 	Make the link between m_element and element_list;
-	This method unlink elements if needed.
+	This method unlinks elements if needed.
 	@param element_list
 */
 void LinkElementCommand::makeLink(const QList<Element *> &element_list)
 {
-	//List is empty, that mean m_element must be free, so we unlink all elements
+	//List is empty, that means m_element must be free, so we unlink all elements
 	if (element_list.isEmpty())
 	{
 		m_element->unlinkAllElements();
@@ -275,8 +275,8 @@ void LinkElementCommand::makeLink(const QList<Element *> &element_list)
 	foreach(Element *elmt, element_list)
 		m_element->linkToElement(elmt);
 
-	/* At this point may be there are unwanted linked elements to m_element.
-	 * We must to unlink it.
+	/* At this point there may be unwanted linked elements to m_element.
+	 * We must unlink it.
 	 * Elements from element_list are wanted so we compare element_list
 	 *  to current linked element of m_element
 	 */