Format markdown.md to comply with what it describes.

When the text says "here are two spaces to force a line break"
there really should be two spaces to force a line break.

doc/user/markdown.md

@@ -750,7 +750,7 @@ This line is separated from the one above by two newlines, so it will be a *sepa
 This line is also a separate paragraph, but...
 This line is only separated by a single newline, so it *does not break* and just follows the previous line in the *same paragraph*.
 
-This line is also a separate paragraph, and...
+This line is also a separate paragraph, and...  
 This line is *on its own line*, because the previous line ends with two spaces. (but still in the *same paragraph*)
 
 spaces.
@@ -763,7 +763,7 @@ This line is separated from the one above by two newlines, so it will be a *sepa
 This line is also a separate paragraph, but...
 This line is only separated by a single newline, so it *does not break* and just follows the previous line in the *same paragraph*.
 
-This line is also a separate paragraph, and...
+This line is also a separate paragraph, and...  
 This line is *on its own line*, because the previous line ends with two spaces. (but still in the *same paragraph*)
 
 spaces.