fix inspection description test
IDEA opens file from command line, same as e.g. WebStorm does
IDEA-85627 amend commit supported in Mercurial

*abstract class for additional commit panel created;
 *common git and mercurial methods  moved to DvcsCommitAdditionalComponent;
 *annotations added;
 *test for hg amend commit added;
 *style
[log] simplify: if-else -> ?: