lexer: temporarily revert #\ patch; keep CR in comment bug fix

This commit temporarily reverts the commit that allows #\ "tcl-style"
comments everywhere and documents them, for the 1.7.1 patch release
cca1f7d18f.

\r is removed from the list of characters not allowed in a comment to
preserve that bugfix.

jq.1.prebuilt

@@ -166,7 +166,7 @@ Use the \fBapplication/json\-seq\fR MIME type scheme for separating JSON texts i
 \fB\-f filename\fR / \fB\-\-from\-file filename\fR:
 .
 .IP
-Read filter from the file rather than from a command line, like awk\'s \-f option\.
+Read filter from the file rather than from a command line, like awk\'s \-f option\. You can also use \'#\' to make comments\.
 .
 .TP
 \fB\-L directory\fR:
@@ -3955,74 +3955,6 @@ The paths provided by this operation point to each of the posts that "stedolan"
 .
 .IP "" 0
 .
-.SH "COMMENTS"
-You can write comments in your jq filters using \fB#\fR\.
-.
-.P
-A \fB#\fR character (not part of a string) starts a comment\. All characters from \fB#\fR to the end of the line are ignored\.
-.
-.P
-If the end of the line is preceded by an odd number of backslash characters, the following line is also considered part of the comment and is ignored\.
-.
-.P
-For example, the following code outputs \fB[1,3,4,7]\fR
-.
-.IP "" 4
-.
-.nf
-
-[
-  1,
-  # foo \e
-  2,
-  # bar \e\e
-  3,
-  4, # baz \e\e\e
-  5, \e
-  6,
-  7
-  # comment \e
-    comment \e
-    comment
-]
-.
-.fi
-.
-.IP "" 0
-.
-.P
-Backslash continuing the comment on the next line can be useful when writing the "shebang" for a jq script:
-.
-.IP "" 4
-.
-.nf
-
-#!/bin/sh \-\-
-# sum \- Output the sum of the given arguments (or stdin)
-# usage: sum [numbers\.\.\.]
-# \e
-exec jq \-\-args \-MRnf "$0" \-\- "$@"
-
-$ARGS\.positional |
-reduce (
-  if \. == []
-    then inputs
-    else \.[]
-  end |
-  \. as $dot |
-  try tonumber catch false |
-  if not or isnan then
-    @json "sum: Invalid number \e($dot)\.\en" | halt_error(1)
-  end
-) as $n (0; \. + $n)
-.
-.fi
-.
-.IP "" 0
-.
-.P
-The \fBexec\fR line is considered a comment by jq, so it is ignored\. But it is not ignored by \fBsh\fR, since in \fBsh\fR a backslash at the end of the line does not continue the comment\. With this trick, when the script is invoked as \fBsum 1 2\fR, \fB/bin/sh \-\- /path/to/sum 1 2\fR will be run, and \fBsh\fR will then run \fBexec jq \-\-args \-MRnf /path/to/sum \-\- 1 2\fR replacing itself with a \fBjq\fR interpreter invoked with the specified options (\fB\-M\fR, \fB\-R\fR, \fB\-n\fR, \fB\-\-args\fR), that evaluates the current file (\fB$0\fR), with the arguments (\fB$@\fR) that were passed to \fBsh\fR\.
-.
 .SH "MODULES"
 jq has a library/module system\. Modules are files whose names end in \fB\.jq\fR\.
 .