Docs fixes for 0.50.0 (#3133)

* docs: typos

* docs: markdown inline code formatting

https://meta.stackexchange.com/questions/82718/how-do-i-escape-a-backtick-within-in-line-code-in-markdown

* docs: remove unused value, move comment, add deps to callback

* docs: add deps to renderMark callback

docs/walkthroughs/05-executing-commands.md

@@ -28,7 +28,7 @@ const App = () => {
         return <BoldMark {...props} />
       }
     }
-  })
+  }, [])
 
   return (
     <Slate editor={editor} defaultValue={defaultValue}>
@@ -97,7 +97,7 @@ const App = () => {
         return <BoldMark {...props} />
       }
     }
-  })
+  }, [])
 
   return (
     <Slate editor={editor} defaultValue={defaultValue}>
@@ -213,7 +213,7 @@ const App = () => {
         return <BoldMark {...props} />
       }
     }
-  })
+  }, [])
 
   return (
     <Slate editor={editor} defaultValue={defaultValue}>
@@ -267,7 +267,7 @@ const App = () => {
         return <BoldMark {...props} />
       }
     }
-  })
+  }, [])
 
   return (
     // Add a  toolbar with buttons that call the same methods.