Feature request: add user-configurable regex Masker

Sections can be ignored by block and in-line quotes ('`', '```'), but this requires modifying comments which otherwise wouldn't quoting. It would be quite powerful to allow users to provide regex which allows them to describe patterns which should be ignored by default.

Consider the following examples:

Sometimes shell commands are useful in code comments, for example:
```bash
# Install dependencies with the following command
# $ some_command.sh
```

Similarly editor commands might have another common syntax:

```lua
-- View active clients with the following command
-- :lua print(vim.inspect(vim.lsp.get_active_clients()))
```

or
```vimscript
" Set color with the following command
" :colo darkblue
```

A user might want to use a regex such as `[\:\$].*$` to ignore comment content which is known to match one of these conventions, which are not necessarily a structured comment syntax.

Start by tracing the existing block and inline quote masking behavior and how user configuration reaches it. Confirm that a configured regex can ignore matching comment content, including the shell and editor-command examples, and add coverage for those cases.

Written by the indexing model from the issue text.