lib/trivial: add boolToYesNo

lib/default.nix

@@ -127,6 +127,7 @@ let
         bitXor
         bitNot
         boolToString
+        boolToYesNo
         mergeAttrs
         flip
         defaultTo

lib/trivial.nix

@@ -240,6 +240,26 @@ in
   */
   boolToString = b: if b then "true" else "false";
 
+  /**
+    Converts a boolean to a string.
+
+    This function uses the strings "yes" and "no" to represent
+    boolean values.
+
+    # Inputs
+
+    `b`
+
+    : The boolean to convert
+
+    # Type
+
+    ```
+    boolToYesNo :: bool -> string
+    ```
+  */
+  boolToYesNo = b: if b then "yes" else "no";
+
   /**
     Merge two attribute sets shallowly, right side trumps left