This upgrades currently used version 10.0.2 from May 2020.
Build process is amended to use terser minification, as it provides
better result as closure-compiler: [1]
Terser (5.3.8):
$ ls -all build/highlight.min.js
-rw-r--r-- 1 davido users 977775 Jan 10 10:04 build/highlight.min.js
Closure-Compiler (v20210106):
$ ls -all build/highlight.min.js
-rw-r--r-- 1 davido users 994034 Jan 9 12:10 build/highlight.min.js
So, terser produces minified build that is 16259 bytes smaller.
Moreover, in latest gerrit releases terser is also used for gr-app.js
minification, so it appears to be consistent to also use terser for
highlight.js minification.
[1] https://github.com/highlightjs/highlight.js/issues/2956
Change-Id: I3a67dc05eb9c4fdac1bf578eacd777dfefb2a360