Small improvements to the error output in component parser to make debugging easier.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 87.70%. Comparing base (1ed61ef) to head (ed92e7c). Report is 2 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1580 +/- ## ======================================= Coverage 87.70% 87.70% ======================================= Files 102 102 Lines 8704 8704 Branches 780 780 ======================================= Hits 7634 7634 Misses 790 790 Partials 280 280 ``` | [Flag](https://app.codecov.io/gh/ros-controls/ros2_control/pull/1580/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-controls) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/ros-controls/ros2_control/pull/1580/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-controls) | `87.70% <66.66%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-controls#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/ros-controls/ros2_control/pull/1580?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-controls) | Coverage Δ | | |---|---|---| | [hardware\_interface/src/component\_parser.cpp](https://app.codecov.io/gh/ros-controls/ros2_control/pull/1580?src=pr&el=tree&filepath=hardware_interface%2Fsrc%2Fcomponent_parser.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-controls#diff-aGFyZHdhcmVfaW50ZXJmYWNlL3NyYy9jb21wb25lbnRfcGFyc2VyLmNwcA==) | `92.91% <66.66%> (ø)` | |