use internal pager for man page as well

calc.go

@@ -620,5 +620,5 @@ func (c *Calc) PrintHelp() {
 		}
 	}
 
-	Pager(output)
+	Pager("rpn help overview", output)
 }

main.go

@@ -18,11 +18,8 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package main
 
 import (
-	"bytes"
 	"fmt"
-	"log"
 	"os"
-	"os/exec"
 	"strings"
 
 	"github.com/chzyer/readline"
@@ -192,19 +189,5 @@ func inputIsStdin() bool {
 }
 
 func man() {
-	var buf bytes.Buffer
-
-	man := exec.Command("less", "-")
-
-	buf.WriteString(manpage)
-
-	man.Stdout = os.Stdout
-	man.Stdin = &buf
-	man.Stderr = os.Stderr
-
-	err := man.Run()
-
-	if err != nil {
-		log.Fatal(err)
-	}
+	Pager("rpn manual page", manpage)
 }

pager.go

@@ -30,6 +30,7 @@ var (
 
 type model struct {
 	content  string
+	title    string
 	ready    bool
 	viewport viewport.Model
 }
@@ -86,7 +87,8 @@ func (m model) View() string {
 }
 
 func (m model) headerView() string {
-	title := titleStyle.Render("RPN Help Overview")
+	// title := titleStyle.Render("RPN Help Overview")
+	title := titleStyle.Render(m.title)
 	line := strings.Repeat("─", max(0, m.viewport.Width-lipgloss.Width(title)))
 	return lipgloss.JoinHorizontal(lipgloss.Center, title, line)
 }
@@ -104,9 +106,9 @@ func max(a, b int) int {
 	return b
 }
 
-func Pager(message string) {
+func Pager(title, message string) {
 	p := tea.NewProgram(
-		model{content: message},
+		model{content: message, title: title},
 		tea.WithAltScreen(),       // use the full size of the terminal in its "alternate screen buffer"
 		tea.WithMouseCellMotion(), // turn on mouse support so we can track the mouse wheel
 	)