Don't quote nil and t in doc strings

This is as per "Tips for Documentation Strings" in the elisp manual.
For consistency, do the same in diagnostics and comments.

2 files changed, 2 insertions, 2 deletions

diff --git a/lisp/calc/calc-yank.el b/lisp/calc/calc-yank.el
index 726a7202a8a..923df5d577f 100644
--- a/lisp/calc/calc-yank.el
+++ b/lisp/calc/calc-yank.el
@@ -149,7 +149,7 @@ as well as set the contents of the Emacs register REGISTER to TEXT."
   "Return the CALCVAL portion of the contents of the Calc register REG,
 unless the TEXT portion doesn't match the contents of the Emacs register REG,
 in which case either return the contents of the Emacs register (if it is
-text) or `nil'."
+text) or nil."
   (let ((cval (cdr (assq reg calc-register-alist)))
         (val (cdr (assq reg register-alist))))
     (if (stringp val)
diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index 1cc11b48ac3..52ed5d7eb3d 100644
--- a/lisp/calc/calc.el
+++ b/lisp/calc/calc.el
@@ -2034,7 +2034,7 @@ See calc-keypad for details."
 ;; (YEAR MONTH DAY math-date-from-gregorian-dt(YEAR MONTH DAY)) for speed.
 (defcustom calc-gregorian-switch nil
   "The first day the Gregorian calendar is used by Calc's date forms.
-This is `nil' (the default) if the Gregorian calendar is the only one used.
+This is nil (the default) if the Gregorian calendar is the only one used.
 Otherwise, it should be a list `(YEAR MONTH DAY)' when Calc begins to use
 the Gregorian calendar; Calc will use the Julian calendar for earlier dates.
 The dates in which different regions of the world began to use the