* doc/as.texinfo (Pseudo Ops): Remove no-file-dir conditional around
menu entry for File; remove version-specific .file operands from menu
description. Replace "LNS directives" menu entry with new entries
for "Loc" and "Loc_mark_labels".
(LNS directives): Split into separate nodes for each directive.
(Loc): New node for .loc directive. Mention that this directive
is for DWARF2 and add a missing article.
(Loc_mark_labels): Likewise for .loc_mark_labels.
(File): Change this node to describe both the default version and
the DWARF2 version of .file. Move the no-file-dir conditional to
include only the default version.