Ms writer: don't escape hyphens.

Previously we escaped hyphens as `\-`, but that's a minus sign.
Closes #4467.

Updated changelog.

changelog

@@ -59,9 +59,12 @@ pandoc (2.1.3)
 
   * Dokuwiki writer: fix LineBreaks in Tables (#4313, Mauro Bieg).
 
-  * Ms writer: asciify pdf anchors, since unicode anchors don't work (#4436).
-    Internal links should be converted automatically, so this shouldn't affect
-    users directly.
+  * Ms writer:
+
+    + Asciify pdf anchors, since unicode anchors don't work (#4436).
+      Internal links should be converted automatically, so this shouldn't
+      affect users directly.
+    + Don't escape hyphens as `\-`; that's for a minus sign (#4467).
 
   * Beamer writer: put hyperlink after `\begin{frame}` and not in the title
     (#4307).  If it's in the title, then we get a titlebar on slides with

src/Text/Pandoc/Writers/Ms.hs

@@ -142,7 +142,6 @@ msEscapes = Map.fromList
               , ('\x2026', "\\&...")
               , ('~', "\\[ti]")
               , ('^', "\\[ha]")
-              , ('-', "\\-")
               , ('@', "\\@")
               , ('\\', "\\\\")
               ]

test/writer.ms

@@ -128,7 +128,7 @@ Here's a regular paragraph.
 In Markdown 1.0.0 and earlier.
 Version 8.
 This line turns into a list item.
-Because a hard\-wrapped line in the middle of a paragraph looked like a list
+Because a hard-wrapped line in the middle of a paragraph looked like a list
 item.
 .PP
 Here's one with a bullet.
@@ -143,7 +143,7 @@ Block Quotes
 .pdfhref O 1 "Block Quotes"
 .pdfhref M "block-quotes"
 .LP
-E\-mail style:
+E-mail style:
 .RS
 .LP
 This is a block quote.
@@ -191,7 +191,7 @@ Code:
 .IP
 .nf
 \f[C]
-\-\-\-\-\ (should\ be\ four\ hyphens)
+----\ (should\ be\ four\ hyphens)
 
 sub\ status\ {
 \ \ \ \ print\ \[dq]working\[dq];
@@ -600,7 +600,7 @@ Code block:
 .IP
 .nf
 \f[C]
-<!\-\-\ Comment\ \-\->
+<!--\ Comment\ -->
 \f[]
 .fi
 .LP
@@ -690,7 +690,7 @@ LaTeX
 .IP \[bu] 3
 @223@
 .IP \[bu] 3
-@p@\-Tree
+@p@-Tree
 .IP \[bu] 3
 Here's some display math:
 .EQ
@@ -760,7 +760,7 @@ Left paren: (
 .PP
 Right paren: )
 .PP
-Greater\-than: >
+Greater-than: >
 .PP
 Hash: #
 .PP
@@ -770,7 +770,7 @@ Bang: !
 .PP
 Plus: +
 .PP
-Minus: \-
+Minus: -
 .HLINE
 .SH 1
 Links
@@ -920,7 +920,7 @@ In a list?
 .IP \[bu] 3
 It should.
 .LP
-An e\-mail address: \c
+An e-mail address: \c
 .pdfhref W -D "mailto:nobody%40nowhere.net" -A "\c" \
  -- "nobody\@nowhere.net"
 \&
@@ -932,7 +932,7 @@ Blockquoted: \c
 \&
 .RE
 .LP
-Auto\-links should not occur here: \f[C]<http://example.com/>\f[]
+Auto-links should not occur here: \f[C]<http://example.com/>\f[]
 .IP
 .nf
 \f[C]