locking.9: Tweak the table column width to fix 80 characters

[zlei]

Summary

While here, add some white spaces to improve the readability of source
code.

MFC after: 1 week

Test Plan

Do lint check, and verify the rendered table,

# mandoc -Tlint share/man/man9/locking.9

# mandoc share/man/man9/locking.9
...
               You want:  spin mtx  mutex/rw  rmlock  sleep rm  sx/lk  sleep
        You have:         --------  --------  ------  --------  -----  ------
        spin mtx          ok        no        no      no        no     no-1
        mutex/rw          ok        ok        ok      no        no     no-1
        rmlock            ok        ok        ok      no        no     no-1
        sleep rm          ok        ok        ok      ok-2      ok-2   ok-2/3
        sx                ok        ok        ok      ok        ok     ok-3
        lockmgr           ok        ok        ok      ok        ok     ok

...

        Context:           spin mtx  mutex/rw  rmlock  sleep rm  sx/lk  sleep
        interrupt filter:  ok        no        no      no        no     no
        interrupt thread:  ok        ok        ok      no        no     no
        callout:           ok        ok        ok      no        no     no
        direct callout:    ok        no        no      no        no     no
        system call:       ok        ok        ok      ok        ok     ok

[ziaee]

This looks better in less, but the syntax is still wrong so I just know in my little heart that it's going to be broken somewhere. Man.f.o is particularly intolerant of column syntax abuse. Try this:

share/man/man9/locking.9

374

You want one column field for each column, which is set to the longest field contained in that column.

375

With the columns fixed above this becomes too far unless this changes too.

376

The width is set by the width set in the Bl macro, so these spaces makes me nervous.

[ziaee]

Oops, forgot to request change

[zlei]

Addressed @ziaee 's comment.

[zlei]

The lint check complains,

% mandoc -Tlint share/man/man9/locking.9  
mandoc: share/man/man9/locking.9:375:23: STYLE: no blank before trailing delimiter: Em        You want:
mandoc: share/man/man9/locking.9:376:16: STYLE: no blank before trailing delimiter: Em You have:
mandoc: share/man/man9/locking.9:411:15: STYLE: no blank before trailing delimiter: Em Context:

That appears to be false report. I can confirm it is caused by the last colon.