docs: update images

(cherry picked from commit f0e2a2ea71)
2019-09-04 12:51:14 +01:00 · 2019-09-04 12:51:14 +01:00 · 32d56fbd93
--- a/docs/language/ql-training-rst/_static-training/java-data-flow-code-example.svg
+++ b/docs/language/ql-training-rst/_static-training/java-data-flow-code-example.svg
--- a/docs/language/ql-training-rst/_static-training/java-expression-ast.svg
+++ b/docs/language/ql-training-rst/_static-training/java-expression-ast.svg
--- a/docs/language/ql-training-rst/_static-training/mismatched-calls-and-returns.svg
+++ b/docs/language/ql-training-rst/_static-training/mismatched-calls-and-returns.svg