Escape column-zero doc parens

* lisp/htmlfontify.el (hfy-display-class):
* lisp/calendar/icalendar.el (icalendar--do-create-ical-alarm):
* lisp/net/shr.el (shr-external-rendering-functions):
* lisp/progmodes/cc-vars.el (c-asymmetry-fontification-flag):
* lisp/textmodes/tildify.el (tildify-tildify):
Escape column-zero doc parens.  A shame bug#21871 remains unfixed.

lisp/calendar/icalendar.el

@@ -1310,7 +1310,7 @@ Returns an alist."
 Argument ADVANCE-TIME is a number giving the time when the alarm
 fires (minutes before the respective event).  Argument ALARM-SPEC
 is a list which must be one of (audio), (display) or
-(email (ADDRESS1 ...)), see `icalendar-export-alarms'.  Argument
+\(email (ADDRESS1 ...)), see `icalendar-export-alarms'.  Argument
 SUMMARY is a string which contains a short description for the
 alarm."
   (let* ((action (car alarm-spec))

lisp/htmlfontify.el

@@ -426,7 +426,7 @@ Some valid class specification elements are:\n
   (type       lucid)
 Multiple values for a tag may be combined, to indicate that any one or more
 of these values in the specification key constitutes a match, eg:\n
-((class color grayscale) (type tty)) would match any of:\n
+\((class color grayscale) (type tty)) would match any of:\n
   ((class color))
   ((class grayscale))
   ((class color grayscale))

lisp/net/shr.el

@@ -149,7 +149,7 @@ cid: URL as the argument.")
   "Alist of tag/function pairs used to alter how shr renders certain tags.
 For instance, eww uses this to alter rendering of title, forms
 and other things:
-((title . eww-tag-title)
+\((title . eww-tag-title)
  (form . eww-tag-form)
  ...)")
 

lisp/progmodes/cc-vars.el

@@ -1641,7 +1641,7 @@ In the fontification engine, it is sometimes impossible to determine
 whether a construct is a declaration or an expression.  This happens
 particularly in C++, due to ambiguities in the language.  When such a
 construct is like \"foo * bar\" or \"foo &bar\", and this variable is non-nil
-(the default), the construct will be fontified as a declaration if there is
+\(the default), the construct will be fontified as a declaration if there is
 white space either before or after the operator, but not both."
   :type 'boolean
   :group 'c)

lisp/textmodes/tildify.el

@@ -350,7 +350,7 @@ If ASK is nil, perform replace without asking user for confirmation.
 
 Returns (count . response) cons where count is number of string
 replacements done and response is one of symbols: t (all right), nil
-(quit), force (replace without further questions)."
+\(quit), force (replace without further questions)."
   (save-excursion
     (goto-char beg)
     (let ((regexp tildify-pattern)