Avoid 'new line' symbols in string edges (YODA writer)

[20DM]

Hi,

I came across a recent submission from CMS that encodes the string edges for the independent axis in Table 2 like so:

  - value: |-
      $c\overline{c}>H\gamma>e
      u_e\mu
      u_\mu\gamma$

which is an edge that involves two new line characters. These are not preserved by the browser-based view of the associated entry: it prints the edge in one line, which was presumably the intention anyway, but that is not necessarily the case for all output formats. I noticed them being propagated through by the YODA writer, which later on causes the reader to crash (which is a separate issue that I will deal with on the YODA side).

For the sake of this entry (and possibly others), I would propose to remove new-line characters entirely from string-based bin edges when assembling the YODA objects, as done in this change set.

[coveralls]

coverage: 91.841%. remained the same
when pulling c05d905 on 20DM:cg_patch_for_newline_symbols
into d543b76 on HEPData:main.

[GraemeWatt]

Thanks for the PR! I'll merge now. It looks like the other output formats all tolerate the newline characters, although I agree it is probably unintentional for ins2709669 and it could complicate later processing of the downloads by users. I therefore edited Table 2 of Version 1 and Table 2 of Version 2 to replace the newline characters by a space (as done in your new code for the YODA writer).