JabRef version 4.3.1, Linux

• I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

I noticed that "Applied numerical mathematics" was not abbreviating and found that this is most likely due to a double space present in its name in the journal list.

Steps to reproduce the behavior:

1. Open the following entry:

@Article{test,
  author  = {Person, A.},
  title   = {A long title},
  journal = {Applied numerical mathematics},
  year    = {2019},
  volume  = {1},
  number  = {1--10},
}

2. Select it and click on Tools > Abbreviate Journal names (ISO)
3. No abbreviations are made, despite the journal being in the "Options > Manage abbreviations" list