go/printer: fix typo

Change-Id: Idf89559c9945c5a8743539658fe92e860fcc6a92
Reviewed-on: https://go-review.googlesource.com/47362Reviewed-by: Matt Layher <mdlayher@gmail.com>

src/go/printer/printer.go

@@ -1348,7 +1348,7 @@ func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{
 
 // Fprint "pretty-prints" an AST node to output.
 // It calls Config.Fprint with default settings.
-// Note that gofmt uses tabs for indentation but spaces for alignent;
+// Note that gofmt uses tabs for indentation but spaces for alignment;
 // use format.Node (package go/format) for output that matches gofmt.
 //
 func Fprint(output io.Writer, fset *token.FileSet, node interface{}) error {