Follow contemporary practices in the Tamil input methods

* lisp/language/ind-util.el (indian-tml-base-digits-table): New table
to translate digits.
(indian-tml-base-table): Don't translate digits.
(indian-tml-itrans-digits-v5-hash): Hashtable that translates digits.

* lisp/leim/quail/indian.el (quail-tamil-itrans-compute-signs-table)
(quail-tamil-itrans-various-signs-table)
(quail-tamil-itrans-various-signs-and-digits-table): Separate out the
digits from the signs table using the function
'quail-tamil-itrans-compute-signs-table'.
(tamil-itrans-digits, tamil-inscript-digits): New input methods that
translates digits.
(tamil-itrans, tamil-inscript): Fix table inclusion.

* etc/NEWS: Announce the change.

Fixes bug#50143.

Copyright-paperwork-exempt: yes

lisp/language/ind-util.el

@@ -255,6 +255,29 @@
      "ണ്" ?ൺ "ന്" ?ൻ "ര്" ?ർ "ല്" ?ൽ "ള്" ?ൾ)))
 
 (defvar indian-tml-base-table
+  '(
+    (;; VOWELS
+     (?அ nil) (?ஆ ?ா) (?இ ?ி) (?ஈ ?ீ) (?உ ?ு) (?ஊ ?ூ)
+     nil nil nil (?ஏ ?ே) (?எ ?ெ) (?ஐ ?ை)
+     nil (?ஓ ?ோ) (?ஒ ?ொ) (?ஔ ?ௌ) nil nil)
+    (;; CONSONANTS
+     ?க nil nil nil ?ங                  ;; GUTTRULS
+     ?ச nil ?ஜ nil ?ஞ                  ;; PALATALS
+     ?ட nil nil nil ?ண                  ;; CEREBRALS
+     ?த nil nil nil ?ந ?ன              ;; DENTALS
+     ?ப nil nil nil ?ம                  ;; LABIALS
+     ?ய ?ர ?ற ?ல ?ள ?ழ ?வ          ;; SEMIVOWELS
+     nil ?ஷ ?ஸ ?ஹ                    ;; SIBILANTS
+     nil nil nil nil nil nil nil nil      ;; NUKTAS
+     "ஜ்ஞ" "க்ஷ")
+    (;; Misc Symbols
+     nil ?ஂ ?ஃ nil ?் nil nil)
+    (;; Digits
+     nil nil nil nil nil nil nil nil nil nil)
+    (;; Inscript-extra (4)  (#, $, ^, *, ])
+     "்ர" "ர்" "த்ர" nil nil)))
+
+(defvar indian-tml-base-digits-table
   '(
     (;; VOWELS
      (?அ nil) (?ஆ ?ா) (?இ ?ி) (?ஈ ?ீ) (?உ ?ு) (?ஊ ?ூ)
@@ -557,6 +580,10 @@
 (defvar indian-tml-itrans-v5-hash
   (indian-make-hash indian-tml-base-table
 			  indian-itrans-v5-table-for-tamil))
+
+(defvar indian-tml-itrans-digits-v5-hash
+  (indian-make-hash indian-tml-base-digits-table
+			  indian-itrans-v5-table-for-tamil))
 )
 
 (defmacro indian-translate-region (from to hashtable encode-p)