Add three states to Text icon on browse toolbar

[craigsapp]

Allow three states for the text icon on the browse bar:

• default: T icon is unselected (search/display both texted and untexted works)
• click once to select T icon (search/display only texted works)
• click once more to delselect T icon and place a ban icon on it (search/display only untexted works)

[craigsapp]

Implemented with commit https://github.com/craigsapp/website-polish-scores/commit/ae90a240eac9ae6b196560b091a03101817e02ad

Default state:

Clicking once highlights the T and only shows/searches texted works:

(same as previously).

Clicking once more will unhighlight the T and place a ban icon on the T, indicating the only textless pieces are being shown/searched:

Clicking again will return to the original state.

Notice that texted works are 5369, textless pieces are 2079, and both are 7448 (the sum of the previous two counts).

[craigsapp]

There are 8 scores that have modernized scores, IIIF markup and do not have text:

These scores, at least the highlighted Benedictus, have text, so something needs to be fixed.

[craigsapp]

Fixed with commit https://github.com/craigsapp/website-polish-scores/commit/d60dbc15f758a567048bb74c139a6d4b661a2f4e

Now there are 59 scores that have modernized scores, IIIF markup and are textless:

The problem was a typo in the variable name input2 (originally left as input after code copy-and-paste).