content: fix awkward phrasing on welcome slide

Fixes golang/go#14245

Change-Id: I77b9bdc910111c13da090983256fd84f4f144359
Reviewed-on: https://go-review.googlesource.com/19324
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/content/welcome.article b/content/welcome.article
index 40adc33..0560410 100644
--- a/content/welcome.article
+++ b/content/welcome.article
@@ -36,8 +36,8 @@
 
 Note that when you click on [[javascript:highlightAndClick("#format")][Format]] or `ctrl-enter`
 the text in the editor is formatted using the
-[[https://golang.org/cmd/gofmt/][gofmt]] tool. You can switch on and off syntax highlighting
-the clicking on [[javascript:highlightAndClick(".syntax-checkbox")][syntax]] button.
+[[https://golang.org/cmd/gofmt/][gofmt]] tool. You can switch syntax highlighting on and off
+by clicking on the [[javascript:highlightAndClick(".syntax-checkbox")][syntax]] button.
 
 When you're ready to move on, click the [[javascript:highlightAndClick(".next-page")][right arrow]] below or type the `PageDown` key.