use mixin in CodeBlock.module.scss

packages/app/src/components/ReactMarkdownComponents/CodeBlock.module.scss

@@ -1,11 +1,9 @@
 @use '~/styles/variables' as var;
 @use '~/styles/bootstrap/init' as bs;
+@use '~/styles/atoms/mixins' as c;
 
 .code-inline {
-  padding: 2px 4px;
-  font-family: var.$font-family-monospace-not-strictly;
-  border: 1px solid;
-  border-radius: bs.$border-radius;
+  @include c.code-inline;
 }
 
 .code-highlighted-title {