Backport: Avoid using obsolete indent-relative-maybe

* lisp/electric.el (electric-indent-functions-without-reindent):
* lisp/indent.el (indent-according-to-mode): Check for
indent-relative-first-indent-point in addition to its obsolete alias
indent-relative-maybe.
* lisp/obsolete/vi.el (vi-com-map): Use
indent-relative-first-indent-point in place of its obsolete alias
indent-relative-maybe.

(cherry picked from commit 0e468a6204)

lisp/electric.el

@@ -223,9 +223,9 @@ Python does not lend itself to fully automatic indentation.")
 
 (defvar electric-indent-functions-without-reindent
   '(indent-relative indent-to-left-margin indent-relative-maybe
-    py-indent-line coffee-indent-line org-indent-line yaml-indent-line
-    haskell-indentation-indent-line haskell-indent-cycle haskell-simple-indent
-    yaml-indent-line)
+    indent-relative-first-indent-point py-indent-line coffee-indent-line
+    org-indent-line yaml-indent-line haskell-indentation-indent-line
+    haskell-indent-cycle haskell-simple-indent yaml-indent-line)
   "List of indent functions that can't reindent.
 If `indent-line-function' is one of those, then `electric-indent-mode' will
 not try to reindent lines.  It is normally better to make the major

lisp/indent.el

@@ -65,15 +65,17 @@ e.g., `c-tab-always-indent', and do not respect this variable."
   "Indent line in proper way for current major mode.
 Normally, this is done by calling the function specified by the
 variable `indent-line-function'.  However, if the value of that
-variable is `indent-relative' or `indent-relative-maybe', handle
-it specially (since those functions are used for tabbing); in
-that case, indent by aligning to the previous non-blank line."
+variable is `indent-relative' or `indent-relative-first-indent-point',
+handle it specially (since those functions are used for tabbing);
+in that case, indent by aligning to the previous non-blank line."
   (interactive)
   (save-restriction
     (widen)
   (syntax-propertize (line-end-position))
   (if (memq indent-line-function
-	    '(indent-relative indent-relative-maybe))
+            '(indent-relative
+              indent-relative-maybe
+              indent-relative-first-indent-point))
       ;; These functions are used for tabbing, but can't be used for
       ;; indenting.  Replace with something ad-hoc.
       (let ((column (save-excursion

lisp/obsolete/vi.el

@@ -132,7 +132,7 @@ command extensions.")
   (define-key vi-com-map "\C-e" 'vi-expose-line-below)
   (define-key vi-com-map "\C-f" 'vi-forward-windowful)
   (define-key vi-com-map "\C-g" 'keyboard-quit)
-  (define-key vi-com-map "\C-i" 'indent-relative-maybe) ; TAB
+  (define-key vi-com-map "\C-i" 'indent-relative-first-indent-point) ; TAB
   (define-key vi-com-map "\C-j" 'vi-next-line) ; LFD
   (define-key vi-com-map "\C-k" 'vi-kill-line) ; extension
   (define-key vi-com-map "\C-l" 'recenter)