Fixed zone links in Frankenstein pages

[timjzee]

I noticed that some displacements in Frankenstein do not follow the encoding guidelines by linking to another zone directly from a metamark tag rather than from an anchor tag. As a result, the linked zones do not appear in the reading text on the website. So far I have found two pages on which this occurs, but more may exist. I have adapted these two pages so that they follow the encoding guidelines produce the correct reading text. I've tested these changes using a script that produces a reading text similar to the one on the website.

[timjzee]

After reading the encoding guidelines again, I noticed that linking to displacements from a metamark tag was actually allowed:

simply place a @corresp attribute in the zone element to link it to either the <anchor/> or <metamark> element within the main zone

I guess that means the code that produces the reading text on the website should probably be updated to support this feature. A programmatic search showed that the reading texts of the following pages should be affected by this issue:

['56-0012', '56-0025', '56-0031', '56-0039', '56-0045', '56-0048', '56-0058', '56-0059', '56-0060', '56-0063', '56-0069', '56-0071', '56-0071', '56-0076', '56-0077', '56-0079', '56-0082', '56-0083', '56-0087', '56-0088', '56-0093', '56-0099', '56-0111', '56-0112', '56-0113', '56-0115', '57-0005', '57-0010', '57-0012', '57-0021', '57-0022', '57-0037', '57-0037', '57-0038', '57-0040', '57-0041', '57-0041', '57-0042', '57-0049', '57-0059', '57-0074', '57-0098', '57-0159', '57-0161', '57-0169', '57-0183', '57-0183']

I will be moving the links in these pages from <metamark> tags to <anchor/> tags anyway for use with my own scripts. I will update the PR when I'm done, and whoever maintains the repo/website can decide whether to fix the reading texts by merging or by changing the code that produces the reading texts.

[timjzee]

All of the relevant pages have been adapted.