Remove JsonVariant::set(char)

CHANGELOG.md

@@ -4,9 +4,9 @@ ArduinoJson: change log
 HEAD
 ----
 
-* Removed `JsonVariant::as<char>()` (issue #1498)
+* Removed support for `char` values, see below (issue #1498)
 
-> ### BREAKING CHANGE
+> ### BREAKING CHANGES
 >
 > We cannot cast a `JsonVariant` to a `char` anymore, so the following will break:
 > ```c++
@@ -16,6 +16,17 @@ HEAD
 > ```c++
 > int8_t age = doc["age"];  // OK
 > ```
+>
+> Similarly, we cannot assign from a `char` anymore, so the following will break:
+> ```c++
+> char age;
+> doc["age"] = age;  // error: no matching function for call to 'VariantRef::set(const char&)'
+> ```
+> Instead, you must use another integral type, such as `int8_t`:
+> ```c++
+> int8_t age;
+> doc["age"] = age;  // OK
+> ```
 
 v6.17.3 (2021-02-15)
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