1-letter typo; thanks to Ella K

git-svn-id: https://svn.r-project.org/R/trunk@87696 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: maechler

src/library/methods/man/Methods_for_Nongenerics.Rd

@@ -63,7 +63,7 @@ available in all these packages.
 However, calls from any package that imports the old version or just
 selects it from the search list will usually \emph{not} select methods.
 
-A an example, consider the function
+As an example, consider the function
 \code{\link{data.frame}()} in the base package.
 This function takes any number of objects as arguments and attempts to combine
 them as variables into a data frame object.