Update docs to new syntax terms

Author: odersky

docs/docs/reference/contextual/inferable-params.md

@@ -101,11 +101,11 @@ Functions like `the` that have only inferable parameters are also called _contex
 Here is the new syntax of parameters and arguments seen as a delta from the [standard context free syntax of Scala 3](http://dotty.epfl.ch/docs/internals/syntax.html).
 ```
 ClsParamClause    ::=  ...
-                    |  ‘given’ (‘(’ [ClsParams] ‘)’ | ContextTypes)
+                    |  ‘given’ (‘(’ [ClsParams] ‘)’ | GivenTypes)
 DefParamClause    ::=  ...
-                    |  InferParamClause
-InferParamClause  ::=  ‘given’ (‘(’ DefParams ‘)’ | ContextTypes)
-ContextTypes      ::=  RefinedType {‘,’ RefinedType}
+                    |  GivenParamClause
+GivenParamClause  ::=  ‘given’ (‘(’ DefParams ‘)’ | GivenTypes)
+GivenTypes        ::=  RefinedType {‘,’ RefinedType}
 
 InfixExpr         ::=  ...
                     |  InfixExpr ‘given’ (InfixExpr | ParArgumentExprs)

docs/docs/reference/contextual/instance-defs.md

@@ -67,11 +67,11 @@ Here is the new syntax of implied instance definitions, seen as a delta from the
 TmplDef          ::=  ...
                   |  ‘implied’ InstanceDef
 InstanceDef      ::=  [id] InstanceParams InstanceBody
-InstanceParams   ::=  [DefTypeParamClause] {InferParamClause}
-InferParamClause ::=  ‘given’ (‘(’ [DefParams] ‘)’ | ContextTypes)
+InstanceParams   ::=  [DefTypeParamClause] {GivenParamClause}
+InferParamClause ::=  ‘given’ (‘(’ [DefParams] ‘)’ | GivenTypes)
 InstanceBody     ::=  [‘for’ ConstrApp {‘,’ ConstrApp }] [TemplateBody]
                    |  ‘for’ Type ‘=’ Expr
-ContextTypes     ::=  RefinedType {‘,’ RefinedType}
+GivenTypes       ::=  RefinedType {‘,’ RefinedType}
 ```
 The identifier `id` can be omitted only if either the `for` part or the template body is present.
 If the `for` part is missing, the template body must define at least one extension method.