[DOCS] Additional documentation for _score accessing

Closes #7043

docs/reference/modules/scripting.asciidoc

@@ -305,8 +305,7 @@ There are a few limitations relative to other script languages:
 === Score
 
 In all scripts that can be used in aggregations, the current
-document's score is accessible in `doc.score`.  When using a `script_score`,
-the current score is available in `_score`.
+document's score is accessible in `_score`.
 
 [float]
 === Computing scores based on terms in scripts
@@ -410,6 +409,13 @@ are much slower to access compared with document fields, as they are not
 loaded into memory. They can be simply accessed using
 `_fields['my_field_name'].value` or `_fields['my_field_name'].values`.
 
+[float]
+=== Accessing the score of a document within a script
+
+When using scripting for calculating the score of a document (for instance, with
+the `function_score` query), you can access the score using the `_score`
+variable inside of a Groovy script.
+
 [float]
 === Source Field
 

docs/reference/search/aggregations/metrics/tophits-aggregation.asciidoc

@@ -184,7 +184,7 @@ relevancy order of the most relevant document in a bucket.
         },
         "top_hit" : {
           "max": {
-            "script": "_doc.score"
+            "script": "_score"
           }
         }
       }