Include the expanded human-readable part when selecting the codex32
checksum. This keeps regular codewords within the 93-symbol BCH period
and rejects the 94- and 95-symbol gap before the long checksum starts
at 96 symbols.
Split regular and long checksum construction and verification so their
periods can be tested independently. Add assertions for both selection
boundaries and the long checksum upper limit.
Refs: https://github.com/bitcoin/bips/pull/2258#issuecomment-5411804501
```
sed -z -i 's/Author: /Authors: /' bip-0*.md
sed -z -i 's/Author: /Authors: /' bip-0*.mediawiki
```
Also align correctly in case of multiple authors.
Also line up with additional items in the lines below.
```
sed -i -z 's/ Post-History: / Discussion: /' bip-0*.md
sed -i -z 's/ Post-History: / Discussion: /' bip-0*.mediawiki
```
* Change master seed to secret in most places, ''t'' to ''k'' and other term fixes
* Replace deleted linebreak, delete vestigal oxford commas
* errors->random errors, fix newlines, vector5: secret seed->codex32 secret
reduced the heading level of checksum and error correction to make the table of contents easier to parse.
Moved Master seed Encoding to be below Unshared Secret.
* BIP93: change codex32 characters to bech32 characters
* Fix hrp length off by 1 bug. Refactor validity condition to read easier.
