minor items

Fix for #1588 and #1595: update single method context `GenericsMapper`

- do not show type vars in javadoc display

extension module error in event console

Fix for #1562: promote exact-match type proposals and demote prefix miss

GROOVY-10651, GROOVY-10671

Fix for #1512: explicit `this` parameter

Groovy for conditional breakpoints, watch expressions, logical structure

and the Debug Console view

for #568 #569

Fix for #1468: enclosing class field preferred over own dynamic property

https://issues.apache.org/jira/browse/GROOVY-10985

GROOVY-10105

Update the Groovy plugin to 2.5.19

for #1395