Documented ObjectListView quick search feature for plugins

[991jo]

Fixes: #20499

[jnovinger]

Thanks for the doc additions, @991jo . It's much appreciated!

I made some notes here and below:

1. Let's clarify that the "Quick Search" field is the UI field, not the field in the filter or the method name.
2. Your sentences appear to all be on a separate line, is there some reason to not have them on the same line and let MkDocs figure out the wrapping?

[991jo]

Regarding each sentence being on it's own line: That's mainly a convention I am sticking to, because it makes changes in diffs clearer, because you only get 1 sentence highlighted instead of the whole paragraph.

Regarding the control of linebreaks: It is complicated. This is primarily an issue of Markdown. CommonMark (an attempt at a markdown spec) seperates a paragraph only if there is a blank line inbetween (see https://spec.commonmark.org/0.31.2/#paragraphs ).
There could be explicit line breaks with two spaces at the end of the line (https://spec.commonmark.org/0.31.2/#hard-line-breaks)

For me this generates one <p> elememt:

<p>The <code>ObjectListView</code> has a field called Quick Search.
For Quick Search to work the corresponding FilterSet has to implement the <code>search</code> method.
This function takes a queryset and can perform arbitrary operations on it and return it.
A common use-case is to search for the given search value in multiple fields:</p>

-> there is no special line break handling in mkdocs afaik and it's all HTML or whatever the other output options of mkdocs are.
However I am also fine with putting the whole paragraph on one line to match the style of the remaining document.

[jnovinger]

I understand the diff-clarity rationale for semantic line breaks, but we do need to maintain consistency with the existing documentation style.

[991jo]

Okay, I updated the file accordingly.