spotless:check inconsistent with spotless:apply - flexmark over MD ending with double EOL

[blacelle]

With the main branch, as reproducible in #1454, one can see that:

With a markdown file ending with a codeBlock, flexmark would format the file with 2 trailing EOL. This looks dubious, but why not. However, if combined with a generic format with endsWithNewLine, it leads to spotlessApply and spotlessCheck to be inconsistent which is a pity.

Typical markdown (\ used to escape markdown in markdown):

\```
   someCode
\```

Typical mvn conf:

<configuration>
      <formats>
	      <!-- you can define as many formats as you want, each is independent -->
	      <format>
		      <!-- define the files to apply to -->
		      <includes>
			      <include>*.md</include>
		      </includes>
		      <endWithNewline/>
	      </format>
      </formats>
      <markdown>
	      <includes>
		      <!-- You have to set the target manually -->
		      <include>**/*.md</include>
	      </includes>
      
	      <flexmark/>
	      <!-- has its own section below -->
      </markdown>
</configuration>

[nedtwigg]

<markdown> is a specialized <format>. Every tag you can use inside <format> is also available inside <markdown>. Also order matters (see #1459). The fix here is:

<configuration>
      <markdown>
	      <includes>
		      <include>**/*.md</include>
	      </includes>
	      <flexmark/>
              <endWithNewline/>
      </markdown>
</configuration>