Fix Search Source File crashing when used with a complex filter

[sebjulliand]

Changes

Fixes #2207

Searching for text in members of a source file would crash if run on a "complex" filter. By complex, I mean a filter whose member filtering term is either a Regex or not a single generic name (XXX*).

This PR fixes this issue, making sure the search runs fine in all cases.
It also fixes some minor issues:

• The search progress message was still Listing members... even after the listing was done and grep was running
• The position used when opening a search hit could be wrong if the line started with one or more whitespaces
• The interval set for displaying different messages during the search was not cleared immediately when the search was over

How to test this PR

1. Run a search on a simple filter
2. Run a search on a complex filter

In both cases, the results must be as expected and only the members actually listed by the filter must be shown in the search result.

Checklist

• have tested my change

[worksofliam]

I will review over the next day or two. Is it worth creating or updating any test cases for this fix?

[worksofliam]

Left some comments. I personally need more context to understand the purpose of this additional property (sorry!)

[sebjulliand]

I will review over the next day or two. Is it worth creating or updating any test cases for this fix?

Here, have a few tests 😊