Improve console output for the absence of `embed-code` tags

[alexander-yevsyukov]

I've tried executing the utility on the set of Markdown files that do not use the <embed-code> tags at all. Here's the console output I got:

Using user's local bash profile.
export plugin already enabled
2026/02/05 19:27:27 INFO starting application, reading args...
2026/02/05 19:27:28 INFO the code fragments are successfully embedded.
2026/02/05 19:27:29 INFO the code fragments are successfully embedded.

The last two lines of the output are problematic:

1. This is not true.
2. We tell it twice.

We should treat the case of absence of embedding tags with a special console message.
The console output should not be duplicated.

Also, please use sentence case for the console reports.