fixing typo in the error message for the binary-function template
fixing typo in the error message for the binary-function template

tectronics/openshadinglanguage,h3rb/openshadinglanguage,h3rb/openshadinglanguage,qdtk/openshadinglanguage,tectronics/openshadinglanguage,h3rb/openshadinglanguage,tectronics/openshadinglanguage,qdtk/openshadinglanguage,qdtk/openshadinglanguage,tectronics/openshadinglanguage,qdtk/openshadinglanguage,code-google-com/openshadinglanguage,code-google-com/openshadinglanguage,code-google-com/openshadinglanguage,h3rb/openshadinglanguage,code-google-com/openshadinglanguage