Fix [[project]] stanza description

[[project]] is now changed to [[projects]] in lock file.

docs/Gopkg.lock.md

@@ -14,11 +14,11 @@ The `Gopkg.lock` file is generated by `dep ensure` and `dep init`. It is the out
 
 `Gopkg.lock` is autogenerated; editing it manually is generally an antipattern. If there is a goal you can only achieve by hand-editing `Gopkg.lock`, it is at least a feature request, and likely a bug.
 
-## `[[project]]`
+## `[[projects]]`
 
-The dependency graph is expressed as a series of `[[project]]` stanzas, each representing a single dependency project. A given project can only appear once in the list, and the version information expressed about them encompasses all contained packages - it is not possible to have multiple packages from a single project at different versions.
+The dependency graph is expressed as a series of `[[projects]]` stanzas, each representing a single dependency project. A given project can only appear once in the list, and the version information expressed about them encompasses all contained packages - it is not possible to have multiple packages from a single project at different versions.
 
-These are all the properties that can appear in a `[[project]]` stanza, and whether or not they are guaranteed to be present/must be present for a stanza to be valid.
+These are all the properties that can appear in a `[[projects]]` stanza, and whether or not they are guaranteed to be present/must be present for a stanza to be valid.
 
 | **Property** | **Always present?** |
 | ------------ | ------------------- |