Minor beam docstring improvements #5577

Job	Run time
Run Tests (macos-latest, 3.10)	5m 50s
Run Tests (macos-latest, 3.11)	6m 14s
Run Tests (macos-latest, 3.12)	6m 53s
Run Tests (windows-latest, 3.10)	7m 54s
Run Tests (windows-latest, 3.11)	9m 39s
Run Tests (windows-latest, 3.12)	10m 59s
Run Tests (macos-13, 3.12, pyuvdata_tests)	16m 5s
Performance Benchmark (macos-latest, 3.12)	4m 18s
Performance Benchmark (windows-latest, 3.12)	9m 3s
Performance Benchmark (ubuntu-latest, 3.12)	4m 16s
Performance Benchmark (macos-13, 3.12, pyuvdata_tests)	7m 29s
	1h 28m 40s

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