fix(glossy): fix forward linking (broken themes)

Fixes [#19](https://github.com/swaits/typst-collection/issues/19).

Themes must emit `entry.label` for terms to be able to forward-link to
their glossary entrie.

glossy/README.md

@@ -253,7 +253,7 @@ Customize glossary appearance by defining a theme with three functions:
   // Individual glossary entry
   entry: (entry, index, total) => {
     // index = entry index, total = total entries in group
-    let output = [#entry.short]
+    let output = [#entry.short#entry.label] // **NOTE:** Label here!
     if entry.long != none {
       output = [#output -- #entry.long]
     }
@@ -280,6 +280,9 @@ Entry fields available to themes:
 - `label`: Term's dictionary label
 - `pages`: Linked page numbers where term appears
 
+**NOTE:** If the theme does not emit `entry.label`, linking form terms to their
+glossary entry will not work.
+
 ## License
 
 This project is licensed under the MIT License.