Explain __mindex snippets a bit better

Author: Sainan

docs/New Features/Mindex Metamethod.md

@@ -8,8 +8,7 @@ In this code, the following occurs:
 2. `__index` returns nil.
 3. Since `__index` returned nil and this lookup is being performed by method invocation syntax (`:`), `__mindex` is queried.
 
-Another example:
-```pluto
+```pluto title="An example showing how __mindex is walked recursively so :insert still works with a custom __mindex"
 local t = setmetatable({}, {
     __mindex = {
         function sum()
@@ -27,8 +26,7 @@ print(t.sum) --> nil
 print(t:sum()) --> 3
 ```
 
-Beware of a caveat:
-```pluto
+```pluto title="An example showing __index taking precedence"
 local t = { 1, 2 }
 print(t:min()) --> 1
 t.min = 1