fakevim: fix indenting

- the indented region has been off by one line as lineForPosition returns 1-based line numbers but QTextDocument::findBlockByNumber expects base 0
- all lines (including first and last line) have to be indented
- if text is collapsed, then findBlockByNumber has to be used instead of findBlockByLineNumber for getting the block containing a line

Merge-request: 96
Reviewed-by: hjk <qtc-committer@nokia.com>

src/plugins/fakevim/fakevimhandler.cpp

@@ -2418,7 +2418,8 @@ void FakeVimHandler::Private::indentRegion(QChar typedChar)
         qSwap(beginLine, endLine);
 
     int amount = 0;
-    emit q->indentRegion(&amount, beginLine, endLine, typedChar);
+    // lineForPosition has returned 1-based line numbers
+    emit q->indentRegion(&amount, beginLine-1, endLine-1, typedChar);
 
     setPosition(firstPositionInLine(beginLine));
     moveToFirstNonBlankOnLine();