Fix style of parameter

Added backticks to "near" when it represents text.

index.bs

@@ -218,14 +218,14 @@ The [=per-type virtual sensor metadata=] [=map=] must have the following [=map/e
     1.  Let |reading| be a new [=sensor reading=].
     1.  Let |keys| be the [=/list=] « "`distance`", "`max`" ».
     1.  [=list/For each=] |key| of |keys|
-        1.  Let |value| be the result of [=parse single-value number reading=] with |parameters| and |key|.
+        1.  Let |value| be the result of invoking [=parse single-value number reading=] with |parameters| and |key|.
             1.  If |value| is **undefined**.
                 1.  Return **undefined**.
         1.  [=map/Set=] |reading|[|keys|] to |value|[|keys|].
-    1.  Let |near| be the result of invoking [=get a property=] from |parameters| with "near".
+    1.  Let |near| be the result of invoking [=get a property=] from |parameters| with "`near`".
         1. If |near|'s type is not Boolean
             1.  Return **undefined**.
-        1.  [=map/Set=] |reading|["near"] to |near|.
+        1.  [=map/Set=] |reading|["`near`"] to |near|.
     1.  Return |reading|.
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