`cols-1` and `cols-5` are not used, but the others are. I should remove `5` in that list at least.

```
$ ag-class "cols-(1|2|3|4|5)"

apps/wiki/templates/wiki/list_files.html:15:          <ul class="documents cols-3">

apps/wiki/templates/wiki/list_documents_for_review.html:24:          <ul class="documents cols-3">

apps/wiki/templates/wiki/list_tags.html:10:        <ul class="documents cols-3">

apps/demos/templates/demos/elements/tech_tags_list.html:3:  <ul class="cols-2">

apps/demos/templates/demos/submit.html:88:                <ul id="tech-tags" class="cols-4">
```