Errors in documentation of fixedNormalSlipFvPatchField.H

Two problems in the Doxygen documentation of the fixedNormalSlip boundary condition:

1. The Description is inaccurate/wrong. It says:

Description
    This boundary condition sets the patch-normal component to a fixed value.

The behaviour implemented in updateCoeffs is:

    Field<Type>::operator=
    (
        nHat*(nHat & fixedValue_)
      + transform(I - sqr(nHat), this->patchInternalField())
    );

I suggest to change the description to:

Description
    This boundary condition sets the patch-normal component to the field (vector 
    or tensor) to the patch-normal component of a user specified field.
    The tangential component is treated as slip, i.e. copied from the internal 
    field.

2. The Usage uses a scalarField as an example but the BC is not defined for these: So I suggest replacing:

Usage
    \table
        Property     | Description             | Required    | Default value
        fixedValue   | fixed value             | yes         |
    \endtable

    Example of the boundary condition specification:
    \verbatim
    <patchName>
    {
        type            fixedNormalSlip;
        fixedValue      uniform 0;     // example entry for a scalar field
    }
    \endverbatim

with

Usage
    \table
        Property     | Description             | Required    | Default value
        fixedValue   | fixed value             | yes         |
    \endtable

    Example of the boundary condition specification:
    \verbatim
    <patchName>
    {
        type            fixedNormalSlip;
        fixedValue      uniform (1 0 0); // example entry for a vector field
    }
    \endverbatim