Doc: Fix typos and add missing words.

Change-Id: I40e4780bcabbca29425945a69d8a0781cd5c0e9f
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>

src/corelib/tools/qalgorithms.qdoc

@@ -764,7 +764,7 @@
     \relates <QtAlgorithms>
     \since 5.2
 
-    Returns the number of bits set in \a v. This number also called
+    Returns the number of bits set in \a v. This number is also called
     the Hamming Weight of \a v.
  */
 

src/corelib/tools/qstring.cpp

@@ -9799,8 +9799,8 @@ QString QString::toHtmlEscaped() const
   if (attribute.name() == QLatin1String("http-contents-length")) //...
   \endcode
 
-  \note There some restrictions when using the MSVC 2010 or 2012 compilers. The example snippets provided here
-  fail to compile with them.
+  \note There are some restrictions when using the MSVC 2010 or 2012 compilers. The example snippets
+  provided here fail to compile with them.
   \list
   \li Concatenated string literals cannot be used with QStringLiteral.
   \code

src/gui/text/qtextlayout.cpp

@@ -207,7 +207,7 @@ void QTextInlineObject::setAscent(qreal a)
 }
 
 /*!
-    Sets the inline object's decent to \a d.
+    Sets the inline object's descent to \a d.
 
     \sa descent(), setAscent(), width(), rect()
 */
@@ -1288,7 +1288,7 @@ void QTextLayout::drawCursor(QPainter *p, const QPointF &pos, int cursorPosition
     After being created, the line can be filled using the setLineWidth()
     or setNumColumns() functions. A line has a number of attributes including the
     rectangle it occupies, rect(), its coordinates, x() and y(), its
-    textLength(), width() and naturalTextWidth(), and its ascent() and decent()
+    textLength(), width() and naturalTextWidth(), and its ascent() and descent()
     relative to the text. The position of the cursor in terms of the
     line is available from cursorToX() and its inverse from
     xToCursor(). A line can be moved with setPosition().