You can only process comments starting with specific characters (just like the "@@" in Javadoc). These characters are called Tokens. The default tokens are @@. Use tokens, if your in-source comments are not related to the following symbol. If Doc-O-Matic is configured to use tokens, all comments that do not start with tokens, are ignored:
This comment will be recognized
//@@ This is a sentence.
The following comment does not start with tokens and is not processed.
// This is a sentence.
Tokens must be the very first string in comments and there must be at least one white space (space, tab, new-line) between text and token. The following comment
//@@This is a sentence.
is not recognized correctly. There is no space between text and token.
You can change the default token on the [General Settings] > Documentation > Comment Finding > Token page.