docker man pages need some love

Executive summary: there are a number of docker-* man pages available under man/, they all need some love.

Formatting

For one thing, formatting/typesetting needs to be cleaned up. The rules (from the top of my head) are:

• literals (like option names, literal values like true or false, or examples) should be bold;
• variable parts (like option values to be substituted) should be italic (note this is frequently rendered as underlined when viewing a man page in a terminal);
• optional parts should be enclosed into square brackets;
• in general, = between the --option and the value should be omitted;
• angle brackets (like <value>) should not be used.

For more rules and examples, check man-pages(7).

For example, here's the correct formatting:

--memory-limit value[SUFFIX]

Sets the memory limit. SUFFIX is optional and can be one of b (bytes), k (kilobytes), m
(megabytes), or g (gigabytes).

Source:

**--memory-limit** *value*[*SUFFIX*]

Sets the memory limit. *SUFFIX* is optional and can be one of
**b** (bytes), **k** (kilobytes), **m** (megabytes), or **g** (gigabytes).

As an example of such work, please see https://github.com/docker/cli/pull/922

Start in the docker-* man pages under man/ and compare their formatting with the man-pages(7) style guide and the example in pull request 922. Update the pages so options, values, literals, optional parts, separators, and angle brackets follow the stated rules; done means the affected pages consistently match those conventions.