fix(Cite): Wrap standalone citations in brackets

.stylelintrc

@@ -40,7 +40,7 @@
         "subpatterns": {
           "semantic": ":--[A-z][A-z0-9]+",
           "element": "(?:\\w*:--[A-z][A-z0-9]+|:root|^stencila-)",
-          "pseudo": "(?::{1,2}(?:\\w|-)+)",
+          "pseudo": "(?::{1,2}(?:\\w|-)+)|(:not(?:\\w|-)+)",
           "combinator": "(:?\\s*(?:>|\\+|~|\\s+|\\|\\|)\\s*)"
         }
       }

src/extensions/cite-apa/styles.css

@@ -20,6 +20,7 @@ See https://en.wikipedia.org/wiki/APA_style#In-text_citations
   }
 }
 
+/* Hide numeric citation format */
 :--Cite > a > :first-child {
   display: none;
 }

src/extensions/cite-numeric/styles.css

@@ -15,10 +15,21 @@
   }
 }
 
+:not(:--CiteGroup) > :--Cite {
+  &::before {
+    content: '[';
+  }
+  &::after {
+    content: ']';
+  }
+}
+
+/* Show numeric citation format */
 :--Cite > a > :first-child {
   display: inline;
 }
 
+/* Hide author-date citation format */
 :--Cite > a > :last-child {
   display: none;
 }