[x/blog] content/context-and-structs: fix duplicate arguments
[x/blog] 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 <605b93664484fed1e671a07bff68da39e73d0174@google.com>
Trust: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
Trust: Jean de Klerk <605b93664484fed1e671a07bff68da39e73d0174@google.com>
X-Blog-Commit: e15ed6808f2cddcdfe63ad7687280a066cf98f54

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