[Documentation:RainbowGrades] Finish Customization Basics (#615)

Complete the guide for the configuration of customization.json found in
Instructor > Course Settings > Rainbow Grades > Customization Basics
(https://submitty.org/instructor/course_settings/rainbow_grades/customization_basics)

Author: zacharymnp

_docs/instructor/course_settings/rainbow_grades/customization_basics.md

@@ -26,12 +26,26 @@ It can contain the following:
 * ``"instructor_notes"``: Shows notes for early warnings, plagiarism, etc. only to the instructor
 * ``"grade_summary"``: Shows the overall score and score for each syllabus bucket (e.g. Homework)
 * ``"grade_details"``: Shows the score for each gradeable
+* ``"section"``: Show the students' registration section.
+* ``"messages"``: Show a text message at the top of the page.
 * ``"final_grade"``: Shows final grade letters and some statistics about the final grade distribution.
+* ``"manual_grade"``: Manually assign final grades to specific students.
 * ``"exam_seating"``: Shows exam seating assignments. To display the assignment on the Submitty course homepage,
   the instructor should make sure "Display Rainbow Grades Custom Message" is enabled in "Course Settings" on the Submitty
   course page.
 * ``"display_rank_to_individual"``: Shows each student's rank in the course, independent of section.
 
+  ```json
+    "display": [
+      "grade_summary",
+      "grade_details",
+      "section",
+      "messages",
+      "final_grade",
+      "manual_grade"
+    ]
+  ```
+
 * **field:** ``"display_benchmark"``  
   **type:** _array of strings_  
   **REQUIRED** if using ``"curve"`` in ``"gradeables"`` described below
@@ -43,6 +57,18 @@ It can contain the following:
    * ``"lowest_a-``, ``"lowest_b-"``, ``"lowest_c-"``, ``"lowest_d"``: Based on curves, the lowest scores that will earn
    the name of the benchmark. 
 
+  ```json
+    "display_benchmark": [
+      "average",
+      "stddev",
+      "perfect",
+      "lowest_a-",
+      "lowest_b-",
+      "lowest_c-",
+      "lowest_d"
+    ]
+  ```
+
 * **field:** ``"benchmark_percent"``  
   **type:** _associative array / mapping from string to float_  
   **REQUIRED** if using ``"curve"`` in ``"gradeables"`` described below, or if any grade-letter benchmarks are used in ``"display_benchmark"`` above.
@@ -51,6 +77,16 @@ It can contain the following:
   necessary to obtain that grade. For example to require an 82% for an A-, there should be an entry in the ``"benchmark_percent"`` array:
   ``"lowest_a-": 0.82``
 
+  To display all benchmarks, include the following:
+  ```json
+    "benchmark_percent": {
+      "lowest_a-": 0.9,
+      "lowest_b-": 0.8,
+      "lowest_c-": 0.7,
+      "lowest_d": 0.6
+    }
+  ```
+
 * **field:** ``"section"``  
   **type:** _associative array / mapping from string to string_  
   **REQUIRED**
@@ -60,34 +96,70 @@ It can contain the following:
   this array will be treated as invalid and ignored. These labels are only displayed
   on the instructor's `output.html`.
 
+  ```json
+    "section": {
+      "1": "1",
+      "2": "2",
+      "3": "3",
+      "4": "4",
+      "5": "5",
+      "6": "6",
+      "7": "7",
+      "8": "8",
+      "9": "9",
+      "10": "10"
+    }
+  ```
+
 * **field:** ``"messages"``  
   **type:** _array of strings_  
 
   These messages will be displayed at the top of the instructor summary and each
   student's individual Rainbow Grades report.
 
+  ```json
+    "messages": [
+      "Example message"
+    ]
+  ```
+
 * **field:** ``"final_cutoff"``  
   **type:** _associative array / mapping from string to float_  
   **REQUIRED** if using ``"final_grade"`` in ``"display"``
 
   Each grade letter that you want should be associated with the minimum overall semester score required to get that grade.
-  This array is unrelated to benchmarks.
+  This array is unrelated to benchmarks. For example:
+
+  ```json
+  "final_cutoff" : {
+    "A": 93.0,
+    "A-": 90.0,
+    "B+": 87.0,
+    "B": 83.0,
+    "B-": 80.0,
+    "C+": 77.0,
+    "C": 73.0,
+    "C-": 70.0,
+    "D+": 67.0,
+    "D": 63.0
+  }
+  ```
 
 * **field:** ``"manual_grade"``  
-  **type:** _associative array / mapping from string to associative array_  
+  **type:** _array of associative arrays_  
 
-  For each student that you want to assign a manual grade to, their id must
-  be mapped to an associative array with a field ``"grade"`` mapped to a string
-  with the letter grade you want to give them, and ``"note"`` containing any note
-  about the adjustment. The note is only visible to the instructor. For example, 
+  For each student that you want to assign a manual grade to, add an item to
+  ``"manual_grade"`` with fields ``"user"``, ``"grade"``, and ``"note"`` containing
+  any note about the adjustment. The note is only visible to the instructor. For example, 
   to give user ``smithj`` a grade lettter of ``D`` with a reason of 
   ``"Put in extraordinary effort."``:
 
   ```json
-  "smithj" : {
+  "manual_grade" : [{
+     "user":"smithj",
      "grade": "D",
      "note": "Put in extraordinary effort."
-  }
+  }]
   ```
 
 * **field:** ``"warning"``