A backslash should not be allowed inside a quoted string unless
it is used to escape another character.
This fixes https://savannah.gnu.org/bugs/?61389.
Bug existed since each of these syntaxes was introduced.
(Awk and Fortran do not know include files with names between
angled brackets, so those regexes are dropped in the bargain.)
Attribute names that are a part of another word should not be colored,
nor should attribute names within strings.
This addresses the other half of https://savannah.gnu.org/patch/?9865.
Original-patch-by: Ryan Westlund <rlwestlund@gmail.com>
Since file-5.10 (end of 2011), libmagic identifies a C file in most
cases as "C source" instead of as "C program". Nano's magic strings
for some other files didn't match any more what file-5.32 currently
produces, either. So, they have been adjusted, new ones added, and
old ones deleted.
This fixes https://savannah.gnu.org/bugs/?52445.
A tag begins not merely with a "<" but it must be followed by an
ASCII alphabetic character or one of "/", "!" and "?".
Further, color all the valid attribute names in red.
