Add new customizable phonetic Tamil input method

* lisp/language/indian.el ("Tamil"): Change the default input method
of the Tamil language environment to the new input method.

* lisp/leim/quail/indian.el
(quail-tamil-itrans-compute-syllable-table): New function extracted
from...
(quail-tamil-itrans-syllable-table): ... here.  Use the above
function.
(quail-tamil-itrans--consonant-order): Auxiliary variable for the
above function.
(quail-tamil-itrans-compute-signs-table): Add new VARIOUS argument.
(quail-tamil-itrans-various-signs-and-digits-table)
(quail-tamil-itrans-various-signs-table): Adjust call to the above
function.

("tamil-phonetic"): Add new input method.
(tamil-input): New group for the input method.
(tamil-translation-rules): New defcustom for the input method to
change the translation rules.

(tamil--syllable-table, tamil--signs-table, tamil--hashtables)
(tamil--vowel-signs): Internal variables used by the input method.
(tamil--setter, tamil--make-tables)
(tamil--update-quail-rules): Internal functions for the input method.
(bug#56323)

* etc/NEWS: Announce the new input method.

1 files changed, 1 insertions, 1 deletions

diff --git a/lisp/language/indian.el b/lisp/language/indian.el
index 2887d410adf..407173827fe 100644
--- a/lisp/language/indian.el
+++ b/lisp/language/indian.el
@@ -109,7 +109,7 @@ are supported in this language environment."))
  "Tamil" '((charset unicode)
            (coding-system utf-8)
            (coding-priority utf-8)
-           (input-method . "tamil-itrans")
+           (input-method . "tamil-phonetic")
            (sample-text . "Tamil (தமிழ்)      வணக்கம்")
            (documentation . "\
 South Indian Language Tamil is supported in this language environment."))