feat(glossy): add type-checking

- adds type-checking via the valkyrie package
- fixes handling of groups parameter on #glossary()
- new test for relevant changes

glossy/tests/group-specified/abbreviations.json

@@ -0,0 +1,11 @@
+{
+  "zbuffer": {
+    "short": "z-bufer",
+    "long": "the depth buffer"
+  },
+  "pbr": {
+    "short": "PBR",
+    "long": "physically based rendering",
+    "group": "abbreviations"
+  }
+}

glossy/tests/group-specified/test.typ

@@ -0,0 +1,33 @@
+#import "/lib.typ": *
+
+#show: init-glossary.with(json("abbreviations.json"))
+
+Reference: @pbr, @zbuffer
+
+
+#let t(g) = [
+  #line(length: 100%)
+  *TESTING:* `#glossary(groups: ` #repr(g) `)`
+  #glossary(groups: g)
+]
+
+#t("abbreviations")                   // "string" : str
+#t(("abbreviations"))                 // ("string") : str
+#t(("abbreviations",))                // ("string",) : array(str)
+#t(("abbreviations","abbreviations")) // ("string","string",) : array(str)
+
+#pagebreak(weak: true)
+
+#t("")                                // empty string should be the empty group
+#t((""))                              // empty string should be the empty group
+#t(("",))                             // empty string should be the empty group
+#t(("",""))                           // empty string should be the empty group
+
+#pagebreak(weak: true)
+
+#t(none)                              // none should be all groups
+#t((none))                            // none should be all groups
+
+#pagebreak(weak: true)
+
+#t(("abbreviations",none))            // try to get both groups