Add cpp to mime.types as text/plain [SPR-16678]

[spring-projects-issues]

Zhang Jie opened SPR-16678 and commented

In most cases, the extend name of "c++" file is cpp, not c++. For Compatibility, I just add cpp to text/plain list.

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Affects: 4.3.14, 5.0.4

Issue Links:

• o/s/mail/javamail mime.types PNG mapped to image/x-png [SPR-15546] #20105 o/s/mail/javamail mime.types PNG mapped to image/x-png

Referenced from: pull request #1772, and commits 1ab0850, 9601d4b

Backported to: 4.3.15