(Multiple languages) Use slightly clearer wording

Author: owen-mc

docs/codeql/codeql-language-guides/analyzing-data-flow-in-csharp.rst

@@ -103,7 +103,7 @@ Unfortunately this will only give the expression in the argument, not the values
      and DataFlow::localFlow(DataFlow::exprNode(src), DataFlow::exprNode(call.getArgument(0)))
    select src
 
-Then we can make the source more specific, for example an access to a public parameter. This query finds instances where a public parameter is used to open a file:
+To restrict sources to only an access to a public parameter, rather than arbitrary expressions, we can modify this query as follows:
 
 .. code-block:: ql
 

docs/codeql/codeql-language-guides/analyzing-data-flow-in-go.rst

@@ -117,7 +117,7 @@ Unfortunately, this only gives the expression in the argument, not the values wh
      DataFlow::localFlow(DataFlow::exprNode(src), DataFlow::exprNode(call.getArgument(0)))
    select src
 
-Then we can make the source more specific, for example an access to a parameter. This query finds where a public parameter is passed to ``os.Open(..)``:
+To restrict sources to only parameters, rather than arbitrary expressions, we can modify this query as follows:
 
 .. code-block:: ql
 

docs/codeql/codeql-language-guides/analyzing-data-flow-in-java.rst

@@ -122,7 +122,7 @@ Unfortunately, this only gives the expression in the argument, not the values wh
      DataFlow::localFlow(DataFlow::exprNode(src), DataFlow::exprNode(call.getArgument(0)))
    select src
 
-Then we can make the source more specific, for example an access to a public parameter. This query finds where a public parameter is passed to ``new FileReader(..)``:
+To restrict sources to only an access to a public parameter, rather than arbitrary expressions, we can modify this query as follows:
 
 .. code-block:: ql