fixed fmodf and added fmodf tests #833

Job	Run time
docs	5m 32s
build-and-test (ubuntu-22.04, NO)	3m 39s
build-and-test (macos-14, NO)	3m 1s
build-and-test (macos-15-intel, NO)	10m 1s
build-and-test (ubuntu-22.04, YES)	3m 57s
build-and-test (windows-latest, NO)	6m 15s
build-and-test (windows-latest, YES)	6m 19s
build-and-test (macos-14, YES)	2m 48s
build-and-test (macos-15-intel, YES)	7m 22s
	48m 54s

Provide feedback