Add fortranplus' "Fortran information & resources"

Fortran information & resources
https://www.fortranplus.co.uk/fortran-information/

Part of: EbookFoundation/free-programming-books#5492

books/free-programming-books.md

@@ -1463,6 +1463,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Fortran 90 Tutorial](http://www.cs.mtu.edu/~shene/COURSES/cs201/NOTES/fortran.html) - C.-K. Shene at Michigan Technological University (HTML)
 * [Fortran 90 Tutorial](https://web.stanford.edu/class/me200c/tutorial_90/) - Sarah T. Whitlock, Paul H. Hargrove at Stanford University (HTML)
 * [FORTRAN Performance Tuning co-Guide (1998)](https://www.ibiblio.org/pub/languages/fortran/unct.html) - Timothy C. Prince (HTML)
+* [Fortran information & resources](https://www.fortranplus.co.uk/fortran-information/) - fortranplus.co.uk (HTML)
 * [Fortran Wiki - Tutorials](http://fortranwiki.org/fortran/show/Tutorials) (HTML)
 * [Fortran. Lecture notes from a class (2020)](http://jupiter.ethz.ch/~pjt/fortran/FortranClass.html) - Paul Tackley (HTML)
 * [Introduction to Fortran](https://qc2-teaching.readthedocs.io/en/latest/programming.html) - Sebastian Ehlert, Julius Stückrath, Marcel Mueller, Marcel Stahn (HTML)