Fix bad hyphenations for US English

Previously, words like "democrat" and "democrats" were mishyphenated,
although TeX hyphenated them properly. The source of the problem was
in the upstream data, where it incorrectly overweighed hyphenation
exceptions like "democratism" and the added patterns resulted in
mishyphenation of words like "democrat".

Now, we restore the pattern file for US English to the original Knuth
list, and instead add the exception list from TUGboat.

Change-Id: If52fe5da0f9e00a822c1c292bb6a2737c9202496
Bug: 35679129
Bug: https://github.com/hyphenation/tex-hyphen/issues/15
Test: hyphtool ./out/host/linux-x86/bin/hyphtool democrat
Test: hyphtool ./out/host/linux-x86/bin/hyphtool democrats
(cherry picked from commit 56ede1d5)