Apply suggestions from code review

Co-authored-by: Harry Maclean <hmac@github.com>

ruby/ql/src/queries/modeling/internal/Summaries.qll

@@ -31,7 +31,7 @@ module Summaries {
     predicate summaryModel(string type, string path, string input, string output) {
       exists(DataFlow::MethodNode methodNode, API::Node paramNode |
         methodNode.getLocation().getFile() instanceof Util::RelevantFile and
-        paramNode.getAValueReachableFromSource() = methodNode.getAReturnNode() and
+        flow(paramNode.asSource(), methodNode.getAReturnNode()) and
         paramNode = getAnyParameterNode(methodNode)
       |
         Util::pathToMethod(methodNode, type, path) and
@@ -59,7 +59,7 @@ module Summaries {
   }
 
   /**
-   * Holds if calls to `(type, path)`, the value referred to by `input`
+   * Holds if in calls to `(type, path)`, the value referred to by `input`
    * can flow to the value referred to by `output`.
    *
    * `kind` should be either `value` or `taint`, for value-preserving or taint-preserving steps,

ruby/ql/src/queries/modeling/internal/Types.qll

@@ -13,7 +13,7 @@ private import Util as Util
  */
 module Types {
   /**
-   * Holds `node` should be seen as having the given `type`.
+   * Holds if `node` should be seen as having the given `type`.
    */
   private predicate valueHasTypeName(DataFlow::LocalSourceNode node, string type) {
     node.getLocation().getFile() instanceof Util::RelevantFile and