fixed broken URL

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@49135 15284696-431f-4ddb-bdfa-cd5b030d7da7

imagery/i.fft/i.fft.html

@@ -42,7 +42,7 @@ d.rast lsat7_2002_70.imag
 
 <ul>
 <li> M. Frigo and S. G. Johnson (1998): "FFTW: An Adaptive Software Architecture
-for the FFT". See <a href=>www.FFTW.org</a>: FFTW is a C subroutine library
+for the FFT". See <a href="http://www.fftw.org">www.FFTW.org</a>: FFTW is a C subroutine library
 for computing the Discrete Fourier Transform (DFT) in one or more
 dimensions, of both real and complex data, and of arbitrary input size.