Convert example to exemplar

* Rename example files to exemplar

See exercism/docs#23

* [Docs] Correct .meta/example references to .meta/exemplar

* [Docs] Use exemplar instead of example

* [Docs] Update example name in file listings

* [Julia] Convert to exemplar.jl

* [elm] Rename .meta/Cook.elm to .meta/Examplar.elm

* [elm] Rename .meta/Examplar.elm .meta/Exemplar.elm

Co-authored-by: Matthieu Pizenberg <matthieu.pizenberg@gmail.com>

Author: ErikSchierboom

exercises/concept/annalyns-infiltration/.meta/example.clj exercises/concept/annalyns-infiltration/.meta/exemplar.clj

@@ -40,7 +40,7 @@ languages
                 ├── .meta
                 |   |── config.json
                 |   |── design.md
-                |   └── Example.clj
+                |   └── Exemplar.clj
                 ├── <NAME>.clj
                 └── <NAME>_test.clj
 </pre>
@@ -51,7 +51,7 @@ The code files are track-specific and should be designed to help the student lea
 
 - `<NAME>.clj`: the Clojure file.
 - `<NAME>_test.clj`: the test suite.
-- `.meta/Example.clj`: the example implementation file.
+- `.meta/Exemplar.clj`: the exemplar implementation file.
 
 ## Step 2: Add documentation files