Consistently use Int. to abbreviate International

[mayrmt]

Some journals have used Int. as an abbreviation for International, some others have used Internat.. The short version is the correct version.

When merging this PR, all journal ins journal_abbreviations_mathematics.csv will consistently abbreviate the word International with Int..

[koppor]

Unfortunately, this file is auto generated. The script used is https://github.com/JabRef/abbrv.jabref.org/blob/main/scripts/update_mathscinet.py. Please see https://github.com/JabRef/abbrv.jabref.org/blob/main/journals/README.md for details.

In short, we propose two fixes:

• A) Update the Python script to automatically correctly abbreviate "Institute"
• B) Reach out to MathSciNet (https://mathscinet.ams.org/mathscinet/help/librarians.html) to get the abbreviations correctly fixed. This would also have impact to other packages (such as shortmathj)