changes.md: [6ce3c0] is fixed. Add some more "known bugs" #4650

Job	Run time
msvc	10m 36s
gcc	11m 20s
msvc (CHECKS=nodep)	10m 32s
gcc (CFLAGS=-DTCL_NO_DEPRECATED=1)	11m 20s
msvc (OPTS=static)	10m 49s
gcc (--disable-shared)	11m 27s
msvc (OPTS=noembed)	10m 9s
msvc (OPTS=symbols)	11m 1s
msvc (OPTS=symbols STATS=compdbg,memdbg)	14m 57s
gcc (--disable-zipfs)	11m 10s
gcc (--enable-symbols)	11m 45s
gcc (--enable-symbols=mem)	13m 10s
gcc (--enable-symbols=all)	14m 42s
	2h 32m 58s

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