cmd/go: fix typo in output of "go help get"

Change-Id: I7e109470e27eb978f920a99f858dbaffa4872eb5
GitHub-Last-Rev: dd684c2481b234f556a1c84c1771f2d8eb8b5ea2
GitHub-Pull-Request: golang/go#28401
Reviewed-on: https://go-review.googlesource.com/c/144837Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/alldocs.go

@@ -2499,7 +2499,7 @@
 // In general, adding a new dependency may require upgrading
 // existing dependencies to keep a working build, and 'go get' does
 // this automatically. Similarly, downgrading one dependency may
-// require downgrading other dependenceis, and 'go get' does
+// require downgrading other dependencies, and 'go get' does
 // this automatically as well.
 //
 // The -m flag instructs get to stop here, after resolving, upgrading,

src/cmd/go/internal/modget/get.go

@@ -78,7 +78,7 @@ to use newer patch releases when available. Continuing the previous example,
 In general, adding a new dependency may require upgrading
 existing dependencies to keep a working build, and 'go get' does
 this automatically. Similarly, downgrading one dependency may
-require downgrading other dependenceis, and 'go get' does
+require downgrading other dependencies, and 'go get' does
 this automatically as well.
 
 The -m flag instructs get to stop here, after resolving, upgrading,