Catch bashlex not implemented errors

[klieret]

catch things like

  "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/swerex/runtime/local.py", line
            76, in _split_bash_command
                parsed = bashlex.parse(inpt)
                         ^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/parser.py",
            line 610, in parse
                parts = [p.parse()]
                         ^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/parser.py",
            line 691, in parse
                tree = theparser.parse(lexer=self.tok, context=self)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/yacc.py", line
            439, in parse
                p.callable(pslice)
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/parser.py",
            line 167, in p_simple_command_element
                p[0] = [_expandword(parserobj, p.slice[1])]
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/parser.py",
            line 145, in _expandword
                parts, expandedword = subst._expandwordinternal(parser,
                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/subst.py", line
            271, in _expandwordinternal
                node, sindex[0] = _paramexpand(parserobj, string, sindex[0])
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/subst.py", line
            165, in _paramexpand
                return _extractcommandsubst(parserobj, string, zindex + 1)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              File "/root/.cache/pipx/7ec35479d91eadd/lib/python3.11/site-packages/bashlex/subst.py", line
            52, in _extractcommandsubst
                raise NotImplementedError('arithmetic expansion')
            NotImplementedError: arithmetic expansion