col(1): Add EXAMPLES section

[fernape]

Summary

Add a small example.
Cross reference clean up for colcrt, nroff and tbl.

Test Plan

• mandoc -Tlint clean
• igor clean
• aspell happy
• man ./col.1 renders the page properly

[gbe]

Some small nits, otherwise LGTM. Thanks for working on the EXAMPLE sections. :)

usr.bin/col/col.1

155 ↗

(On Diff #78442)

I would use vi here, since it is included in FreeBSD's base.

157 ↗

(On Diff #78442)

See above.

[fernape]

usr.bin/col/col.1

155 ↗

(On Diff #78442)

I don't think vi can read from standard input:

fernape@beastie:~/FreeBSD-repos/base/head$ man ls | col -b | view
ex/vi: Vi's standard input and output must be a terminal
fernape@beastie:~/FreeBSD-repos/base/head$ man ls | col -b | vi -R -
vi: -s option is only applicable to ex.

[gbe]

@bcr would it be okay to use a ports application in a manual page from base?

[bcr]

I think it is OK, since vim is popular enough, even though it is not in the base system. If we can't find an example that uses a base system utility, that is.

[fernape]

Reformulate example to avoid referencing utilities not in base.

Use grep(1) to search for text that would not be found if the output of man(1)
were not filtered previously.

With this, all three utilities are in base and it is simple enough to remove
col(1) from the job in the example and see that the text is not found.

[gbe]

LGTM.

You could also include the vim example after @bcr comment states that it would be okay.

[fernape]

In D26864#599542, @gbe wrote:

LGTM.

You could also include the vim example after @bcr comment states that it would be okay.

I finally landed the approved version as it is now.

Thanks for reviewing this!