ICU-22947 Update user guide for MF2 #85

Job	Run time
icu4c-store-perf-libs	0s
icu4c-windows-cygwin-gcc	26m 5s
icu4c-windows-msvc-postmerge (x64, Debug)	10m 31s
icu4j-mvn-init-cache	29s
icu4c-windows-msvc-postmerge (x64, Release)	8m 5s
icu4c-windows-msvc-postmerge (x86, Debug)	12m 15s
icu4c-windows-msvc-postmerge (x86, Release)	8m 43s
icu4c-performance-tests	0s
icu4c-performance-tests-with-files	0s
icu4c-strsrchperf	0s
icu4j-unicodesetperf	0s
icu4j-little-endian-data-test	10m 31s
icu4j-ucharacterperf	0s
icu4j-decimalformatperf	0s
icu4j-converterperf	0s
icu4j-dateformatperf	0s
icu4j-normperf	0s
Copy perf data to remote repo for visualization	0s
	1h 16m 39s

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