add trailing newlines to command help messages (#77)

The main --help message already has a trailing newline, but the messages
for check, fmt, and interface did not.

Author: kalgynirae

src/cli/check.zig

@@ -289,6 +289,7 @@ const Command = struct {
             \\                    and SuperHTML files. 
             \\
             \\   --help, -h       Prints this help and exits.
+            \\
         , .{});
 
         std.process.exit(1);

src/cli/fmt.zig

@@ -321,6 +321,7 @@ const Command = struct {
             \\                      and SuperHTML files. 
             \\
             \\   --help, -h         Prints this help and exits.
+            \\
         , .{});
 
         std.process.exit(1);

src/cli/interface.zig

@@ -175,6 +175,7 @@ const Command = struct {
             \\                    and SuperHTML files. 
             \\
             \\   --help, -h       Prints this help and exits.
+            \\
         , .{});
 
         std.process.exit(1);