hgignore.5: mark file names and cmdline options as literal text

doc/hgignore.5.txt

@@ -24,14 +24,14 b' DESCRIPTION'
 The working directory of a Mercurial repository will often contain
 files that should not be tracked by Mercurial. These include backup
 files created by editors and build products created by compilers.
-These files can be ignored by listing them in a `.hgignore` file in
-the root of the working directory. The `.hgignore` file must be
+These files can be ignored by listing them in a ``.hgignore`` file in
+the root of the working directory. The ``.hgignore`` file must be
 created manually. It is typically put under version control, so that
 the settings will propagate to other repositories with push and pull.
 
 An untracked file is ignored if its path relative to the repository
 root directory, or any prefix path of that path, is matched against
-any pattern in `.hgignore`.
+any pattern in ``.hgignore``.
 
 For example, say we have an an untracked file, ``file.c``, at
 ``a/b/file.c`` inside our repository. Mercurial will ignore ``file.c``
@@ -43,7 +43,7 b' of how to configure these files. Look fo'
 "ui" section.
 
 To control Mercurial's handling of files that it manages, see the
-|hg(1)|_ man page. Look for the "-I" and "-X" options.
+|hg(1)|_ man page. Look for the "``-I``" and "``-X``" options.
 
 SYNTAX
 ------