inline syntax highlight metadata keys in doc

docs/customization.rst

@@ -110,7 +110,7 @@ Metadata for a single page
 ==========================
 
 Each page can support a set of page-specific options. These are configured using metadata roles.
-Each metadata is evaluated as a ``:key: value`` pair.
+Each metadata is evaluated as a :rst:`:key: value` pair.
 
 .. seealso::
     Review the
@@ -122,7 +122,7 @@ Each metadata is evaluated as a ``:key: value`` pair.
     Unlike, newer versions of mkdocs-material theme, this theme also supports the use of a textual
     "hero" section.
 
-    To set the hero's text for an individual page, use the ``:hero:`` metadata field for the desired page.
+    To set the hero's text for an individual page, use the :rst:`:hero:` metadata field for the desired page.
     If not specified, then the page will not have a hero section.
 
     .. code-block:: rst
@@ -152,7 +152,7 @@ Each metadata is evaluated as a ``:key: value`` pair.
 
         :hide_toc:
 
-    Instead of using ``:hide_toc:``, this theme can also use the ``:tocdepth:`` metadata to hide the
+    Instead of using :rst:`:hide_toc:`, this theme can also use the :rst:`:tocdepth:` metadata to hide the
     page's Table of Contents.
 
     .. code-block:: rst