content/context-and-structs: fix duplicate arguments

I renamed the argument to avoid duplicate variable names on example.

Change-Id: I7fea6d55c713880e5597f6e923e03c05e19792fd
GitHub-Last-Rev: b52867484baf5258325bbb941b8805e814acac1c
GitHub-Pull-Request: golang/blog#49
Reviewed-on: https://go-review.googlesource.com/c/blog/+/296169
Reviewed-by: Jean de Klerk <deklerk@google.com>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Jean de Klerk <deklerk@google.com>
diff --git a/content/context-and-structs.article b/content/context-and-structs.article
index 581f5e6..a4242ef 100644
--- a/content/context-and-structs.article
+++ b/content/context-and-structs.article
@@ -32,7 +32,7 @@
   _ = ctx // A per-call ctx is used for cancellation, deadlines, and metadata.
 }
 
-func (w *Worker) Process(ctx context.Context, w *Work) error {
+func (w *Worker) Process(ctx context.Context, work *Work) error {
   _ = ctx // A per-call ctx is used for cancellation, deadlines, and metadata.
 }
 ```
@@ -56,7 +56,7 @@
   _ = w.ctx // A shared w.ctx is used for cancellation, deadlines, and metadata.
 }
 
-func (w *Worker) Process(w *Work) error {
+func (w *Worker) Process(work *Work) error {
   _ = w.ctx // A shared w.ctx is used for cancellation, deadlines, and metadata.
 }
 ```