Add provides GoInfo to source and library rules (#4458)

**What type of PR is this?**
Bug fix

**What does this PR do? Why is it needed?**
Adds the missing `provides` tag to go_library and go_source

**Which issues(s) does this PR fix?**

**Other notes for review**

Author: fionera

go/private/rules/library.bzl

@@ -197,6 +197,7 @@ go_library = rule(
     } | CGO_ATTRS,
     fragments = CGO_FRAGMENTS,
     toolchains = [GO_TOOLCHAIN] + CGO_TOOLCHAINS,
+    provides = [GoInfo],
     doc = """This builds a Go library from a set of source files that are all part of
     the same package.<br><br>
     ***Note:*** For targets generated by Gazelle, `name` is typically the last component of the path,

go/private/rules/source.bzl

@@ -82,6 +82,7 @@ go_source = rule(
         "_cgo_context_data": attr.label(default = "//:cgo_context_data_proxy"),
     },
     toolchains = [GO_TOOLCHAIN],
+    provides = [GoInfo],
     doc = """This declares a set of source files and related dependencies that can be embedded into one of the
     other rules.
     This is used as a way of easily declaring a common set of sources re-used in multiple rules.<br><br>