Search fails on invalid regex

[andrewjanssen]

Description

Oops, my recent PR introduced a bug where, if a user types a search string that is an invalid regex, the filter fails to be applied. Instead, the other kinds of matching like substring matching should still be performed. For example, PR 60 broke the search for (. This PR fixes that.

This PR also corrects a typo in the README related to regex search.

Type of change

[x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Manual testing.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules