update outdated description in README.md and api.md

README.md

@@ -119,12 +119,12 @@ See [the usage document](docs/usage.md) for more details.
 ## Documents
 
 - [Checks](docs/checks.md): Full list of all checks done by actionlint with example inputs, outputs, and playground links.
-- [Installation](docs/install.md): Installation instructions. Prebuilt binaries, Homebrew package, a Docker image, building from
-  source, a download script (for CI) are available.
+- [Installation](docs/install.md): Installation instructions. Prebuilt binaries, a Docker image, building from
+  source, a download script (for CI), supports by several package managers are available.
 - [Usage](docs/usage.md): How to use `actionlint` command locally or on GitHub Actions, the online playground, an official Docker
   image, and integrations with reviewdog, Problem Matchers, super-linter, pre-commit, VS Code.
-- [Configuration](docs/config.md): How to configure actionlint behavior. Currently only labels of self-hosted runners can be
-  configured.
+- [Configuration](docs/config.md): How to configure actionlint behavior. Currently the labels of self-hosted runners and the
+  configuration variables can be set.
 - [Go API](docs/api.md): How to use actionlint as Go library.
 - [References](docs/reference.md): Links to resources.
 

docs/api.md

@@ -4,7 +4,13 @@ Go API
 
 This document describes how to use [actionlint](..) as Go library.
 
-actionlint can be used from Go programs. See [the documentation][apidoc] to know the list of all APIs. It contains
+actionlint can be used from Go programs by importing the module.
+
+```go
+import "github.com/rhysd/actionlint"
+```
+
+See [the documentation][apidoc] to know the list of all APIs. It contains
 a workflow file parser built on top of `go-yaml/yaml`, expression `${{ }}` lexer/parser/checker, etc.
 
 Followings are unexhaustive list of interesting APIs.