[docs] do not use a subdir for GitHub workflows

.mapping.json

@@ -30,8 +30,8 @@
   ".github/workflows/build_and_test_ondemand.yml":"ydb/github_toplevel/.github/workflows/build_and_test_ondemand.yml",
   ".github/workflows/build_and_test_provisioned.yml":"ydb/github_toplevel/.github/workflows/build_and_test_provisioned.yml",
   ".github/workflows/docker_publish.yml":"ydb/github_toplevel/.github/workflows/docker_publish.yml",
-  ".github/workflows/docs/build.yaml":"ydb/github_toplevel/.github/workflows/docs/build.yaml",
-  ".github/workflows/docs/release.yaml":"ydb/github_toplevel/.github/workflows/docs/release.yaml",
+  ".github/workflows/docs_build.yaml":"ydb/github_toplevel/.github/workflows/docs_build.yaml",
+  ".github/workflows/docs_release.yaml":"ydb/github_toplevel/.github/workflows/docs_release.yaml",
   ".github/workflows/nightly_run.yaml":"ydb/github_toplevel/.github/workflows/nightly_run.yaml",
   ".github/workflows/pr_check.yml":"ydb/github_toplevel/.github/workflows/pr_check.yml",
   ".github/workflows/prewarm-ccache.yml":"ydb/github_toplevel/.github/workflows/prewarm-ccache.yml",