fix readme document and code comment

README.md

@@ -18,7 +18,7 @@ Other real-world examples:
 ## Installation
 
 Download binary from [the releases page](https://github.com/rhysd/changelog-from-release/releases) or
-build from sources with Go toolchain.
+build from sources with Go toolchain (1.21 or later).
 
 ```
 $ go install github.com/rhysd/changelog-from-release/v3@latest
@@ -36,6 +36,8 @@ $ changelog-from-release > CHANGELOG.md
 $ cat CHANGELOG.md
 ```
 
+For more command line usage, see the `-help` output.
+
 Automation with [GitHub Actions][gh-actions] is also offered. Please read
 [action's README](./action/README.md) for more details.
 
@@ -46,8 +48,6 @@ Automation with [GitHub Actions][gh-actions] is also offered. Please read
     github_token: ${{ secrets.GITHUB_TOKEN }}
 ```
 
-For more usage, see `-help` output.
-
 
 ## Reference auto linking
 
@@ -110,7 +110,7 @@ cat <<-EOS > CHANGELOG.md
 Changelog
 =========
 
-This is a footer.
+This is a header.
 
 EOS
 

reflink.go

@@ -329,7 +329,7 @@ func (l *Reflinker) linkURL(n *ast.AutoLink) {
 	}
 
 	// Search the offset of the start of the URL. When the text is a child of some other node, URL
-	// may not appear just after the previous node. The example is **https://...** where URL appers
+	// may not appear just after the previous node. The example is **https://...** where URL appears
 	// after the first **.
 	offset := bytes.Index(l.src[start:], url)
 	if offset < 0 {