Fix some typos I noticed in the Programming Cryptol book.

[sauclovian-g]

Fix some typos I noticed in the Programming Cryptol book.

• p-1 bits in an IEEE float refers to the significand, not the mantissa, at least according to the latest preferred terminology, which aims to keep the word "mantissa" for the full mantissa including the units bit;
• reciprocal rather than reciprocol;
• the example in 1.23 had the wrong module declarations; also insert a separator word between the verbatim blocks so they can be told apart.

Closes #1630.

[RyanGlScott]

@kquick, there's a CI failure in the build-pages-docs job:

Error: Error message: Unable to get ACTIONS_ID_TOKEN_REQUEST_URL env variable
    at Function.<anonymous> (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:71:1)
    at Generator.next (<anonymous>)
    at /home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:8:1
    at new Promise (<anonymous>)
    at __webpack_modules__.8041.__awaiter (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:4:1)
    at Function.getIDToken (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:57:1)
    at Object.<anonymous> (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/core.js:315:1)
    at Generator.next (<anonymous>)
    at /home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/core.js:27:1
    at new Promise (<anonymous>)
Error: Ensure GITHUB_TOKEN has permission "id-token: write".

Likely because @sauclovian-g is submitting a PR from a fork rather than a branch of the cryptol repo. Do you think that we should skip this part of the CI for PRs for forks?

[RyanGlScott]

Thanks for the PR! The CI failure appears wholly unrelated to the changes in this PR, so let's go ahead and land this.

[kquick]

@kquick, there's a CI failure in the build-pages-docs job:

Error: Error message: Unable to get ACTIONS_ID_TOKEN_REQUEST_URL env variable
    at Function.<anonymous> (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:71:1)
    at Generator.next (<anonymous>)
    at /home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:8:1
    at new Promise (<anonymous>)
    at __webpack_modules__.8041.__awaiter (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:4:1)
    at Function.getIDToken (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/oidc-utils.js:57:1)
    at Object.<anonymous> (/home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/core.js:315:1)
    at Generator.next (<anonymous>)
    at /home/runner/work/_actions/actions/deploy-pages/v2/node_modules/@actions/core/lib/core.js:27:1
    at new Promise (<anonymous>)
Error: Ensure GITHUB_TOKEN has permission "id-token: write".

Likely because @sauclovian-g is submitting a PR from a fork rather than a branch of the cryptol repo. Do you think that we should skip this part of the CI for PRs for forks?

Surprisingly difficult to find details on how to do this, but #1633 will hopefully effect this change.