_content/doc/modules: fix typos

Fixes golang/go#50291

Change-Id: Id6bec449991de4ca0fb075ab534652b23266ee93
Reviewed-on: https://go-review.googlesource.com/c/website/+/373854
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: hopehook <hopehook@golangcn.org>
Run-TryBot: hopehook <hopehook@golangcn.org>
diff --git a/_content/doc/modules/managing-dependencies.md b/_content/doc/modules/managing-dependencies.md
index 802e9c3..9a068af 100644
--- a/_content/doc/modules/managing-dependencies.md
+++ b/_content/doc/modules/managing-dependencies.md
@@ -523,8 +523,8 @@
 
 Go modules are frequently developed and distributed on version control servers
 and module proxies that aren’t available on the public internet. You can set the
-`GOPRIVATE` environment variables. You can set the `GOPRIVATE` environment variable
-to configure the `go` command to download and build modules from private sources.
+`GOPRIVATE` environment variable to configure the `go` command
+to download and build modules from private sources.
 Then the go command can download and build modules from private sources.
 
 The `GOPRIVATE` or `GONOPROXY` environment variables may be set to lists of glob