pgAdmin 4 commit: 1) Improve wording for script header while generating

1) Improve wording for script header while generating the script using the schema diff tool.
2) Fixed an issue where closing the query tool panel throws an error.
3) Fixed schema diff close panel issue.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=0d77bc305e1a7d58158145df870a6bbe85fe84da

Modified Files
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web/pgadmin/tools/datagrid/__init__.py             | 48 +++++++++++-----------
web/pgadmin/tools/schema_diff/__init__.py          | 36 +++++++++++++++-
.../schema_diff/static/js/schema_diff_hook.js      |  2 +-
.../tools/schema_diff/static/js/schema_diff_ui.js  | 16 ++++----
4 files changed, 68 insertions(+), 34 deletions(-)