docs/presence/rpolicy.md: Fix MD033 warnings

The following warnings are generated by using markdownlint analysis:
```
docs/presence/rpolicy.md:37:6 MD033/no-inline-html Inline HTML [Element: code]
docs/presence/rpolicy.md:37:1 MD033/no-inline-html Inline HTML [Element: pre]
docs/presence/rpolicy.md:50:5 MD033/no-inline-html Inline HTML [Element: b]
docs/presence/rpolicy.md:50:8 MD033/no-inline-html Inline HTML [Element: i]
```
Refer to markdown-lint [1] to fix MD033
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/033-no-inline-html.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I31748039b2f6a5bae46245a416dbde2eed4f3699
diff --git a/docs/presence/rpolicy.md b/docs/presence/rpolicy.md
index b1da85c..6d7af45 100644
--- a/docs/presence/rpolicy.md
+++ b/docs/presence/rpolicy.md
@@ -34,7 +34,7 @@
 
 ## Example
 
-<pre><code>
+```json
 [
   {
     "name": "fan0",
@@ -42,14 +42,12 @@
     "methods": [
       {
         "type": "tach",
-        "sensors": [
-          "fan0_0"
-        ]
+        "sensors": ["fan0_0"]
       }
     ],
-    <b><i>"rpolicy": {
+    "rpolicy": {
       "type": "anyof"
-    }"</i></b>
+    }
   }
 ]
-</code></pre>
+```