Document full syntaxes of \SHOWFILE and \ASSERT(STR)

[muzimuzhi]

I think syntaxes are preferable than textual descriptions.

Before

After

[muzimuzhi]

Hmm looks like <file name> is preferred than <filename>.

In l3kernel repository,

$ grep -rn '\\\(Arg\|meta\){filename}' **/*.dtx | wc -l
       3
$ grep -rn '\\\(Arg\|meta\){file name}' **/*.dtx | wc -l
      47

[muzimuzhi]

Coincidentally, l3build.dtx uses "filename" only. I'll leave it as is.

[car222222]

You expect consistency here?? :-)