patch 9.1.1252: typos in code and docs related to 'diffopt' "inline:"

Problem:  Typos in code and docs related to 'diffopt' "inline:".
          (after v9.1.1243)
Solution: Fix typos and slightly improve the docs.
          (zeertzjq)

closes: #16997

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/diff.txt

@@ -1,4 +1,4 @@
-*diff.txt*      For Vim version 9.1.  Last change: 2024 Mar 26
+*diff.txt*      For Vim version 9.1.  Last change: 2024 Mar 28
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -243,12 +243,11 @@ The diffs are highlighted with these groups:
 				highlight the exact difference between the
 				two.  Will respect any 'diffopt' flag that
 				affects internal diff.
-				Not used when `inline:` set to "none".
-|hl-DiffTextAdd|  DiffTextAdd	Added text inside a Changed line. Similar to
+				Not used when `inline:` is set to "none".
+|hl-DiffTextAdd|  DiffTextAdd	Added text inside a Changed line.  Similar to
 				DiffText, but used when there is no
-				corresponding text in other buffers.  Will not
-				be used when `inline:` is set to "simple" or
-				"none".
+				corresponding text in other buffers.  Not used
+				when `inline:` is set to "simple" or "none".
 |hl-DiffDelete|	DiffDelete	Deleted lines.  Also called filler lines,
 				because they don't really exist in this
 				buffer.

runtime/doc/options.txt

@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2025 Mar 27
+*options.txt*	For Vim version 9.1.  Last change: 2025 Mar 28
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -2982,8 +2982,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 				none    Do not perform inline highlighting.
 				simple  Highlight from first different
 					character to the last one in each
-					line. This is the default if nothing
-					is set.
+					line.  This is the default if no
+					`inline:` value is set.
 				char    Use internal diff to perform a
 					character-wise diff and highlight the
 					difference.

src/structs.h

@@ -3606,7 +3606,7 @@ typedef struct diffline_change_S diffline_change_T;
 struct diffline_change_S
 {
     colnr_T	dc_start[DB_COUNT];	// byte offset of start of range in the line
-    colnr_T	dc_end[DB_COUNT];	// 1 paste byte offset of end of range in line
+    colnr_T	dc_end[DB_COUNT];	// 1 past byte offset of end of range in line
     int		dc_start_lnum_off[DB_COUNT];	// starting line offset
     int		dc_end_lnum_off[DB_COUNT];	// end line offset
 };

src/testdir/test_diffmode.vim

@@ -2463,8 +2463,8 @@ func Test_diff_inline()
   "   on a different line.
   call WriteDiffFiles(buf,
         \ ["abcdefghijklmno", "anchor1",
-        \  "abcdefghijklmno", "anchor2",
-        \  "abcdefghijklmno", "anchor3",
+        \  "abcdefghijklmno", "anchor2",
+        \  "abcdefghijklmno", "anchor3",
         \  "test", "multiline"],
         \ ["a?c?e?g?i?k???o", "anchor1",
         \  "a??de?????klmno", "anchor2",
@@ -2505,7 +2505,7 @@ func Test_diff_inline_multibuffer()
   call WriteDiffFiles3(buf,
         \ ["That is buffer1.", "anchor", "Some random text", "anchor"],
         \ ["This is buffer2.", "anchor", "Some text", "anchor", "buffer2/3"],
-        \ ["This is buffer3. Last.", "anchor", "Some more", "text here.", "anchor", "only in buffer2/3", "not in buffer1"])
+        \ ["This is buffer3. Last.", "anchor", "Some more", "text here.", "anchor", "only in buffer2/3", "not in buffer1"])
   call VerifyInternal(buf, "Test_diff_inline_multibuffer_01", " diffopt+=inline:char")
 
   " Close one of the buffers and make sure it updates correctly

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1252,
 /**/
     1251,
 /**/