What regular expressions does Find & Replace for Text Editing use?

Question

Google Chrome

Good afternoon.
The question of such a plan.
There is a site on wordpress, in the administrative part of the site there are forms for entering / formatting text (large text), which, when published, is displayed on the front to the user.
The task is to remove double, triple ... spaces from the text, remove line gaps from the text and, if necessary, auto-correct the necessary words, numbers, letters, symbols.

Not one of the autocorrect extensions for Google Chrome did not fit. (Apparently due to the fact that the text is in a certain input form and plugins simply do not see it) The Find & Replace for Text Editing extension was found, which works BUT

a little bit .
Plugin in normal search/autochange mode doesn't see 2, 3, 4... problems, it sees only single ones.
Text, numbers, symbols sees normally.

The extension seems to be able to work with regular ones. BUT
The only thing it could do was to understand a regular expression like this "\s\s\s*" then it removes double or more spaces throughout the text.
When I want to remove empty lines and give it the regular expression "\r\n", the extension does not understand it.
I get the impression that the only regex characters it understands are "\s" and "*".

Actually the question is:

1. Maybe someone knows what characters this extension understands, can immediately share the regular expression that will solve my questions.
2. Perhaps there is another autocorrect extension that will solve my questions.

P.s. I’ll answer the question right away, I can’t install the plugin for Wordpress, tk. I don't have permission to install them.

Thank you very much in advance and I ask you not to swear at me much, I understand that the task seems to be simple, but with certain conditions it becomes much more complicated.

Answer 1

Try to just transfer the text to Word (it will be transferred with formatting). Next Find and Replace => Replace => More => Special. There are a lot of possibilities, including the removal of empty lines.