Java: Update the java internal documentation for models.

Author: michaelnebel

java/ql/lib/semmle/code/java/dataflow/ExternalFlow.qll

@@ -39,7 +39,7 @@
  *    "Argument[n]", "Argument[n1..n2]", "ReturnValue":
  *    - "": Selects a write to the selected element in case this is a field.
  *    - "Argument[n]": Selects an argument in a call to the selected element.
- *      The arguments are zero-indexed, and `-1` specifies the qualifier.
+ *      The arguments are zero-indexed, and `this` specifies the qualifier.
  *    - "Argument[n1..n2]": Similar to "Argument[n]" but select any argument in
  *      the given range. The range is inclusive at both ends.
  *    - "ReturnValue": Selects a value being returned by the selected element.
@@ -50,14 +50,14 @@
  *    - "": Selects a read of a selected field, or a selected parameter.
  *    - "Argument[n]": Selects the post-update value of an argument in a call to the
  *      selected element. That is, the value of the argument after the call returns.
- *      The arguments are zero-indexed, and `-1` specifies the qualifier.
+ *      The arguments are zero-indexed, and `this` specifies the qualifier.
  *    - "Argument[n1..n2]": Similar to "Argument[n]" but select any argument in
  *      the given range. The range is inclusive at both ends.
  *    - "Parameter": Selects the value of a parameter of the selected element.
  *      "Parameter" is also allowed in case the selected element is already a
  *      parameter itself.
  *    - "Parameter[n]": Similar to "Parameter" but restricted to a specific
- *      numbered parameter (zero-indexed, and `-1` specifies the value of `this`).
+ *      numbered parameter (zero-indexed, and `this` specifies the value of `this`).
  *    - "Parameter[n1..n2]": Similar to "Parameter[n]" but selects any parameter
  *      in the given range. The range is inclusive at both ends.
  *    - "ReturnValue": Selects the return value of a call to the selected element.