buildlab: replace echos in usage with heredoc

buildlab.in

@@ -221,33 +221,35 @@ build_package() {
 }
 
 usage() {
-	echo "buildlab $program_version"
-	echo " "
-	echo "Common options:"
-	echo " "
-	echo " -q	Quiet operation"
-	echo " -p	Path to buildroot"
-	echo " "
-	echo "Creating build roots (buildlab -C):"
-	echo " "
-	echo " -m	APK repository mirror"
-	echo " -v	APK distribution version"
-	echo " -a	APK repository architecture"
-	echo " -k	Enable APK caching"
-	echo " "
-	echo "Updating build roots (buildlab -u):"
-	echo " "
-	echo " No special options."
-	echo " "
-	echo "Building packages (buildlab -b):"
-	echo " "
-	echo " -b	APKBUILD file"
-	echo " "
-	echo "Examples:"
-	echo " "
-	echo "sudo ./buildlab -C -p /home/nenolod/buildroot -m dl-3.alpinelinux.org -v edge -a x86_64"
-	echo "sudo ./buildlab -b /home/nenolod/aports/main/gnome-panel/APKBUILD -p /home/nenolod/buildroot"
-	echo "sudo ./buildlab -u -p /home/nenolod/buildroot"
+	cat <<-EOF
+		buildlab $program_version
+
+		Common options:
+
+		 -q  Quiet operation
+		 -p  Path to buildroot
+
+		Creating build roots (buildlab -C):
+
+		 -m  APK repository mirror
+		 -v  APK distribution version
+		 -a  APK repository architecture
+		 -k  Enable APK caching
+
+		Updating build roots (buildlab -u):
+
+		 No special options.
+
+		Building packages (buildlab -b):
+
+		 -b  APKBUILD file
+
+		Examples:
+
+		 sudo ./buildlab -C -p /home/nenolod/buildroot -m dl-3.alpinelinux.org -v edge -a x86_64
+		 sudo ./buildlab -b /home/nenolod/aports/main/gnome-panel/APKBUILD -p /home/nenolod/buildroot
+		 sudo ./buildlab -u -p /home/nenolod/buildroot
+	EOF
 }
 
 unset force