Add function family desc

Author: reikookamoto

_pkgdown.yml

@@ -9,13 +9,16 @@ template:
   theme: atom-one-light
 
 reference:
-  - title: ":magic_wand: Derive new variables"
+  - title: ":magic_wand: Derive"
+    desc: "Create new variables"
     contents:
       - starts_with("derive_")
-  - title: ":twisted_rightwards_arrows: Recode missing value placeholders"
+  - title: ":twisted_rightwards_arrows: Recode"
+    desc: "Take care of missing value placeholders (e.g., 8, 9, -88888)"
     contents:
       - recode_missing
-  - title: ":mag: Inspect data quality"
+  - title: ":mag: Inspect"
+    desc: "Assess data quality before performing analysis"
     contents:
       - check_response_consistency
       - find_matching_pairs