Fix guidelines button and remove typo

Author: Grant Murphy

docs/rules/rule-intro.md

@@ -7,4 +7,3 @@ The following guidelines attempt to explain the issues, and best practices aroun
 problems that gosec helps to identify in your source code. If you have any questions, or feel
 something is unclear please do not hesitate to raise an issue or reach out to us on slack.
 
--

website/pages/en/index.js

@@ -79,7 +79,7 @@ class HomeSplash extends React.Component {
         <div className="inner">
           <ProjectTitle />
           <PromoSection>
-            <Button href={docUrl('guidelines.html')}>Read our guidelines</Button>
+            <Button href={docUrl('rules/rule-intro.html')}>Read our guidelines</Button>
             <Button href="https://github.com/securego/gosec">Try out our tools</Button>
             <Button href="http://securego.herokuapp.com/">Join our community</Button>
           </PromoSection>