Fix the format string of font size in points in the inspector #9298

Job	Run time
prettier	34s
test	2m 31s
alejandra	33s
typos	36s
build-macos	4m 37s
build-bench	55s
build (namespace-profile-ghostty-md, aarch64-linux)	53s
build-linux-libghostty	52s
build (namespace-profile-ghostty-md, x86_64-linux)	1m 29s
build (namespace-profile-ghostty-md, x86-windows-gnu)	56s
build-macos-matrix	11m 23s
build-nix (namespace-profile-ghostty-md)	2m 11s
build-windows	7m 15s
build-nix (namespace-profile-ghostty-md-arm64)	5m 2s
build (namespace-profile-ghostty-md, x86_64-windows-gnu)	52s
GTK adwaita=true x11=true	58s
test-macos	3m 11s
GTK adwaita=true x11=false	55s
GTK adwaita=false x11=true	56s
GTK adwaita=false x11=false	1m 4s
	47m 43s

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