Document key for exercise files (#407)

Document  key for exercise  iles

Co-authored-by: ee7 <45465154+ee7@users.noreply.github.com>

Author: ErikSchierboom

building/configlet/lint.md

@@ -249,6 +249,8 @@ The `config.json` file should have the following checks:
 - The `"forked_from"` values must not have duplicates
 - The `"language_versions"` key is optional
 - The `"language_versions"` value must be a string
+- The `"representer.version"` key is optional
+- The `"representer.version"` value must be an integer >= 1
 - The `"icon"` key is optional
 - The `"icon"` value must be a kebab-case string²
 
@@ -321,6 +323,8 @@ The `config.json` file should have the following checks:
 - The `"language_versions"` value must be a string
 - The `"test_runner"` key is optional
 - The `"test_runner"` value must be a boolean
+- The `"representer.version"` key is optional
+- The `"representer.version"` value must be an integer >= 1
 
 ### Rule: exercises/{concept|practice}/<slug>/.approaches/config.json is valid
 

building/tracks/concept-exercises.md

@@ -325,6 +325,8 @@ This file contains meta information on the exercise:
 - `blurb`: A short description of this exercise. Its length must be <= 350. Markdown is _not_ supported (required)
 - `source`: The source this exercise is based on (optional)
 - `source_url`: The URL of the source this exercise is based on (optional)
+- `representer`: Meta information related to how the representer processes this file (optional)
+  - `version`: An integer for the version of the representer to use for the exercise (required if parent key is present)
 - `icon`: The slug of the icon (see [the full list of icons][exercise-icons]). If not specified, the exercise's slug will be used (optional)
 
 If someone is both an author _and_ a contributor, only list that person as an author.
@@ -362,6 +364,9 @@ Assume that the user `FSharpForever` has written an exercise called `log-levels`
   "blurb": "Learn how to work with strings by processing log lines.",
   "source": "Wikipedia",
   "source_url": "https://en.wikipedia.org/wiki/Log_file",
+  "representer": {
+    "version": 2
+  },
   "icon": "logs"
 }
 ```

building/tracks/practice-exercises.md

@@ -287,6 +287,8 @@ This file contains meta information on the exercise:
 - `source`: The source this exercise is based on (optional)
 - `source_url`: The URL of the source this exercise is based on (optional)
 - `test_runner`: Indicates if solutions of this exercise should be tested in the test runner. Defaults to `true` if not specified. (optional)
+- `representer`: Meta information related to how the representer processes this file (optional)
+  - `version`: An integer for the version of the representer to use for the exercise (required if parent key is present)
 - `icon`: The slug of the icon (see [the full list of icons][exercise-icons]). If not specified, the exercise's slug will be used (optional)
 
 If someone is both an author _and_ a contributor, only list that person as an author.