docs(checkbox/radio): Fix accessibility warnings in code snippets

src/components/Checkbox/Checkbox.md

@@ -7,18 +7,21 @@ A stand-alone checkbox is used for a single option that the user can turn on or
 <a href="https://www.nngroup.com/articles/checkboxes-vs-radio-buttons/" target="_blank">Reference</a>
 
 ```
-<Box tag="fieldset" between={2}>
-  <Text bold size="medium">
-    Show me deals for:
-  </Text>
-  <Checkbox name="services" value="mobility" label="Mobility" />
-  <Checkbox name="services" value="internet" label="Internet" />
-  <Checkbox name="services" value="tv" label="TV" />
-  <Checkbox name="services" value="home-phone" label="Home Phone" />
-</Box>
+<fieldset>
+  <Box tag="fieldset" between={2}>
+    <legend>
+      <Text bold size="medium">
+        Show me deals for:
+      </Text>
+    </legend>
+    <Checkbox name="services" value="mobility" label="Mobility" />
+    <Checkbox name="services" value="internet" label="Internet" />
+    <Checkbox name="services" value="tv" label="TV" />
+    <Checkbox name="services" value="home-phone" label="Home Phone" />
+  </Box>
+</fieldset>
 ```
 
-
 ### Getting feedback for an unchecked checkbox
 
 Use the feedback and error props to give the user feedback regarding a missed checkbox by highlighting the label, checkbox element and adding an error message stating how to proceed.

src/components/Radio/Radio.md

@@ -8,7 +8,7 @@ Radio buttons are used when there is a list of two or more options that are mutu
 
 * Use when there can only be exactly one choice from mulitple options
 * Use there are 2-6 options to choose from
-* Use  [`Select`](#select) (dropdown) when there are over 6 options
+* Use [`Select`](#select) (dropdown) when there are over 6 options
 
 ```
 initialState = {
@@ -17,11 +17,15 @@ initialState = {
 
 const setChoice = (event) => setState({choice: event.target.value});
 
-<Box tag="fieldset" between={2}>
-  <Text bold size="medium">
-    How would you like to recieve your monthly bill?
-  </Text>
-  <Radio label="e.Bill" name="monthly-bill" value="e.Bill" checked={state.choice === "e.bill"} onChange={setChoice} />
-  <Radio label="Paper bill" name="monthly-bill" value="paper bill" checked={state.choice === "paper bill"} onChange={setChoice} />
-</Box>
+<fieldset>
+  <Box tag="fieldset" between={2}>
+    <legend>
+      <Text bold size="medium">
+        How would you like to recieve your monthly bill?
+      </Text>
+    </legend>
+    <Radio label="e.Bill" name="monthly-bill" value="e.Bill" checked={state.choice === "e.bill"} onChange={setChoice} />
+    <Radio label="Paper bill" name="monthly-bill" value="paper bill" checked={state.choice === "paper bill"} onChange={setChoice} />
+  </Box>
+</fieldset>
 ```