Typos and small documentation improvements

[hi-ilkin]

Small issues like typos, formatting issues etc will be collected under this issue. So far findings:

• Sentence is not complete https://github.com/parashardhapola/scarf/blob/28cc97801ad9fcb7b88e05ec139e0ca1e61d07fb/docs/source/vignettes/zarr_explanation.md?plain=1#L66
• renaming is unnecessary https://github.com/parashardhapola/scarf/blob/28cc97801ad9fcb7b88e05ec139e0ca1e61d07fb/docs/source/vignettes/multiple_modalities.md?plain=1#L47-L53
• Formatting issues for ‘normed__I__hvgs’
  https://github.com/parashardhapola/scarf/blob/28cc97801ad9fcb7b88e05ec139e0ca1e61d07fb/docs/source/vignettes/zarr_explanation.md?plain=1#L85