vim-patch:9.1.1065: no digraph for "Approaches the limit" (#32289)

Problem:  no digraph for "Approaches the limit"
Solution: Add the digraph using .= (Hans Ginzel)

Add digraph Approaches the Limit

≐ U+2250 https://www.fileformat.info/info/unicode/char/2250/index.htm

closes: vim/vim#16508

3a621188ee

Co-authored-by: Hans Ginzel <hans@matfyz.cz>

runtime/doc/digraph.txt

@@ -119,8 +119,8 @@ see them.
 
 On most systems Vim uses the same digraphs.  They work for the Unicode and
 ISO-8859-1 character sets.  These default digraphs are taken from the RFC1345
-mnemonics.  To make it easy to remember the mnemonic, the second character has
-a standard meaning:
+mnemonics (with some additions).  To make it easy to remember the mnemonic,
+the second character has a standard meaning:
 
 	char name		char	meaning ~
 	Exclamation mark	!	Grave
@@ -1064,6 +1064,7 @@ the 1', 2' and 3' digraphs.
   ≅	?=	2245	8773	APPROXIMATELY EQUAL TO
   ≈	?2	2248	8776	ALMOST EQUAL TO
   ≌	=?	224C	8780	ALL EQUAL TO
+  ≐	.=	2250	8784	APPROACHES THE LIMIT
   ≓	HI	2253	8787	IMAGE OF OR APPROXIMATELY EQUAL TO
   ≠	!=	2260	8800	NOT EQUAL TO
   ≡	=3	2261	8801	IDENTICAL TO

src/nvim/digraph.c

@@ -1023,6 +1023,7 @@ static digr_T digraphdefault[] =
   { '?', '=', 0x2245 },
   { '?', '2', 0x2248 },
   { '=', '?', 0x224c },
+  { '.', '=', 0x2250 },
   { 'H', 'I', 0x2253 },
   { '!', '=', 0x2260 },
   { '=', '3', 0x2261 },

test/old/testdir/test_digraph.vim

@@ -40,6 +40,9 @@ func Test_digraphs()
   " Quadruple prime
   call Put_Dig("'4")
   call assert_equal("⁗", getline('.'))
+  " APPROACHES THE LIMIT
+  call Put_Dig(".=")
+  call assert_equal("≐", getline('.'))
   " Not a digraph
   call Put_Dig("a\<bs>")
   call Put_Dig("\<bs>a")