Update Javadoc for FirebaseCrashlytics.java (#2492)

Author: elenadoty

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/CustomKeysAndValues.java

@@ -20,7 +20,7 @@
 
 /**
  * Helper class which handles the storage and conversion to strings of key/value pairs with
- * heterogenous value types.
+ * heterogeneous value types.
  */
 public class CustomKeysAndValues {
 

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/FirebaseCrashlytics.java

@@ -444,7 +444,7 @@ public void setCustomKey(@NonNull String key, @NonNull String value) {
 
   /**
    * Sets multiple custom keys and values that are associated with subsequent fatal and non-fatal
-   * reports. This method is intended as an alternative to setCustomKey in order to reduce the
+   * reports. This method is intended as an alternative to `setCustomKey` in order to reduce the
    * computational load of writing out multiple key/value pairs at the same time.
    *
    * <p>Multiple calls to this method with the same key update the value for that key.
@@ -457,7 +457,7 @@ public void setCustomKey(@NonNull String key, @NonNull String value) {
    *
    * <p>Accepts a maximum of 64 key/value pairs. If calling this method results in the number of
    * custom keys exceeding this limit, only some of the keys will be logged (however many are needed
-   * to get to 64). Which are logged versus dropped is unpredictable as there is no intrinsic
+   * to get to 64). Which keys are logged versus dropped is unpredictable as there is no intrinsic
    * sorting of keys. Keys or values that exceed 1024 characters are truncated.
    *
    * @param keysAndValues A dictionary of keys and the values to associate with each key