If the argument to make_file can act like a file, return it.
This is useful for code that calls command functions, but doesn't
want to send I/O through the filesystem.
header = header-raw.tmpl
footer = ""
changeset = changeset-raw.tmpl
annotateline = "<tr class="parity#parity#"><td class="annotate"><a href="?cmd=changeset;node=#node#">#author#@#rev#</a></td><td><pre>#line#</pre></td></tr>"
difflineplus = "#line#"
difflineminus = "#line#"
difflineat = "#line#"
diffline = "#line#"
changesetparent = "# parent: #node#"
filenodelink = "#file#"
filerevision = filerevision-raw.tmpl
fileline = "#line#"
diffblock = "#lines#"
filediff = filediff-raw.tmpl