Add. 18,187, https://bl.syriac.uk/ms/1125, may need physDesc at containing ms level

https://bl.syriac.uk/ms/1125 may be an example of a multi-part manuscript where we still want to include information in the `physDesc/p` at the containing ms (msDesc) level in addition to at the part level. Look into this ms to determine which aspects need to go at the top level