MdEditOperations: Ctrl+U to delete till the space of block

src/utils/veditutils.h

@@ -25,6 +25,7 @@ public:
     // Need to call setTextCursor() to make it take effect.
     static void moveCursorFirstNonSpaceCharacter(QTextCursor &p_cursor,
                                                  QTextCursor::MoveMode p_mode);
+
     // Indent current block as next/previous block.
     // Return true if some changes have been made.
     // @p_cursor will be placed at the position after inserting leading spaces.

src/utils/vvim.cpp

@@ -1383,7 +1383,7 @@ bool VVim::handleKeyPressEvent(int key, int modifiers, int *p_autoIndentPos)
     case Qt::Key_AsciiCircum:
     {
         if (modifiers == Qt::ShiftModifier) {
-            // ~, go to first non-space character of current line (block).
+            // ^, go to first non-space character of current line (block).
             tryGetRepeatToken(m_keys, m_tokens);
             if (!m_keys.isEmpty()) {
                 // Not a valid sequence.

src/vmdeditoperations.cpp

@@ -565,8 +565,15 @@ bool VMdEditOperations::handleKeyU(QKeyEvent *p_event)
         if (cursor.atBlockStart()) {
             ret = cursor.movePosition(QTextCursor::PreviousWord, QTextCursor::KeepAnchor);
         } else {
+            int indent = VEditUtils::fetchIndentation(cursor.block());
+            int pib = cursor.positionInBlock();
+            if (pib <= indent) {
                 ret = cursor.movePosition(QTextCursor::StartOfLine, QTextCursor::KeepAnchor);
+            } else {
+                ret = cursor.movePosition(QTextCursor::PreviousCharacter, QTextCursor::KeepAnchor, pib - indent);
             }
+        }
+
         if (ret) {
             cursor.removeSelectedText();
         }