Watcher: Error catching fixed (#1573) (#278)

* Watcher: Error catching fixed 

There was a typo/mistake in the example try-catch block. It should either be `error` in the catch clause or `e` in the statement.
```
 try {
        .....
    } catch (error) {
      answer.value = 'Error! Could not reach the API. ' + error
    }
```

* Vue SFC Playground link updated 

The playground links are updated to match the code changes.

* Playground: API URL in options API fixed

Fixed the API URL typo in the options API playground

Changes were made from https://yesno.wtf/apdi to https://yesno.wtf/api

Co-authored-by: Moshiur Rahman <unimrgm@gmail.com>

Author: jay-es

src/guide/essentials/watchers.md

@@ -30,7 +30,7 @@ export default {
       try {
         const res = await fetch('https://yesno.wtf/api')
         this.answer = (await res.json()).answer
-      } catch (e) {
+      } catch (error) {
         this.answer = 'Error! Could not reach the API. ' + error
       }
     }
@@ -46,7 +46,7 @@ export default {
 <p>{{ answer }}</p>
 ```
 
-[Try it in the Playground](https://sfc.vuejs.org/#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)
+[Try it in the Playground](https://sfc.vuejs.org/#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)
 
 The `watch` option also supports a dot-delimited path as the key:
 
@@ -81,7 +81,7 @@ watch(question, async (newQuestion, oldQuestion) => {
     try {
       const res = await fetch('https://yesno.wtf/api')
       answer.value = (await res.json()).answer
-    } catch (e) {
+    } catch (error) {
       answer.value = 'Error! Could not reach the API. ' + error
     }
   }
@@ -97,7 +97,7 @@ watch(question, async (newQuestion, oldQuestion) => {
 </template>
 ```
 
-[Try it in the Playground](https://sfc.vuejs.org/#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)
+[Try it in the Playground](https://sfc.vuejs.org/#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)
 
 ### Watch Source Types