(backport) Make "-index" example more illustrative, Remove stray brac… #4630

Job	Run time
gcc	3m 21s
gcc (CFLAGS=-DTCL_NO_DEPRECATED=1)	3m 23s
gcc (--disable-shared)	3m 19s
gcc (--disable-zipfs)	3m 28s
gcc (--enable-symbols)	3m 34s
gcc (--enable-symbols=mem)	4m 55s
gcc (--enable-symbols=all)	6m 19s
gcc (CFLAGS=-ftrapv)	3m 40s
gcc (CFLAGS=-m32 CPPFLAGS=-m32 LDFLAGS=-m32 --disable-64bit)	3m 39s
	35m 38s

Provide feedback