conflicts: use clearer wording for missing newline comment

The current comment uses `[noeol]`, which can be difficult to
understand. In this commit, the brackets are changed to parentheses to
make it clear that there is no semantic meaning to the comment, and the
wording is changed to be more clear to the user.

docs/conflicts.md

@@ -185,19 +185,18 @@ New Heading
 >>>>>>>>>>>>>>> Conflict 1 of 1 ends
 ```
 
-## Conflicts with missing terminating newline (`[noeol]`)
+## Conflicts with missing terminating newline
 
 When materializing conflicts, `jj` outputs them in a line-based format. This
 format is easiest to interpret for text files that consist of a series of lines,
 with each line terminated by a newline character (`\n`). This means that a text
 file should either be empty, or it should end with a newline character.
 
-While most text files follow this convention, some do not. To handle this case,
-when `jj` encounters a missing terminating newline character in a conflict, it
-will add a `[noeol]` comment to the conflict markers to indicate that the
-"end-of-line" (EOL) character was missing. If you don't care about whether your
-file ends with a terminating newline character, you can generally ignore this
-comment and resolve the conflict normally.
+While most text files follow this convention, some do not. When `jj` encounters
+a missing terminating newline character in a conflict, it will add a comment to
+the conflict markers to make the conflict easier to interpret. If you don't care
+about whether your file ends with a terminating newline character, you can
+generally ignore this comment and resolve the conflict normally.
 
 For instance, if a file originally contained `grape` with no terminating newline
 character, and one person changed `grape` to `grapefruit`, while another person
@@ -206,14 +205,13 @@ would look like this:
 
 ```
 <<<<<<< Conflict 1 of 1
-+++++++ Contents of side #1 [noeol]
++++++++ Contents of side #1 (no terminating newline)
 grapefruit
-%%%%%%% Changes from base to side #2 [-noeol]
+%%%%%%% Changes from base to side #2 (adds terminating newline)
 -grape
 +grape
 >>>>>>> Conflict 1 of 1 ends
 ```
 
-The `[-noeol]` comment for the diff section indicates that the base (`-`) was
-missing a terminating newline character. A resolution of this conflict could be
-`grapefruit\n`, with the terminating newline character added.
+Therefore, a resolution of this conflict could be `grapefruit\n`, with the
+terminating newline character added.

lib/src/conflicts.rs

@@ -59,13 +59,13 @@ pub const MIN_CONFLICT_MARKER_LEN: usize = 7;
 const CONFLICT_MARKER_LEN_INCREMENT: usize = 4;
 
 /// Comment for missing terminating newline in a term of a conflict.
-const NO_EOL_COMMENT: &str = " [noeol]";
+const NO_EOL_COMMENT: &str = " (no terminating newline)";
 
 /// Comment for missing terminating newline in the "add" side of a diff.
-const ADD_NO_EOL_COMMENT: &str = " [+noeol]";
+const ADD_NO_EOL_COMMENT: &str = " (removes terminating newline)";
 
 /// Comment for missing terminating newline in the "remove" side of a diff.
-const REMOVE_NO_EOL_COMMENT: &str = " [-noeol]";
+const REMOVE_NO_EOL_COMMENT: &str = " (adds terminating newline)";
 
 fn write_diff_hunks(hunks: &[DiffHunk], file: &mut dyn Write) -> io::Result<()> {
     for hunk in hunks {

lib/tests/test_conflicts.rs

@@ -627,14 +627,14 @@ fn test_materialize_conflict_no_newlines_at_eof() {
     let materialized =
         &materialize_conflict_string(store, path, &conflict, ConflictMarkerStyle::Diff);
     insta::assert_snapshot!(materialized,
-        @r###"
+        @r##"
     <<<<<<< Conflict 1 of 1
-    %%%%%%% Changes from base to side #1 [-noeol]
+    %%%%%%% Changes from base to side #1 (adds terminating newline)
     -base
-    +++++++ Contents of side #2 [noeol]
+    +++++++ Contents of side #2 (no terminating newline)
     right
     >>>>>>> Conflict 1 of 1 ends
-    "###
+    "##
     );
     // The conflict markers are parsed with the trailing newline, but it is removed
     // by `update_from_content`
@@ -2057,7 +2057,7 @@ fn test_update_conflict_from_content_no_eol() {
     +++++++ Contents of side #1
     base
     left
-    %%%%%%% Changes from base to side #2 [noeol]
+    %%%%%%% Changes from base to side #2 (no terminating newline)
     -base
     +right
     >>>>>>> Conflict 2 of 2 ends
@@ -2096,9 +2096,9 @@ fn test_update_conflict_from_content_no_eol() {
     +++++++ Contents of side #1
     base
     left
-    ------- Contents of base [noeol]
+    ------- Contents of base (no terminating newline)
     base
-    +++++++ Contents of side #2 [noeol]
+    +++++++ Contents of side #2 (no terminating newline)
     right
     >>>>>>> Conflict 2 of 2 ends
     "##
@@ -2197,15 +2197,15 @@ fn test_update_conflict_from_content_no_eol_in_diff_hunk() {
     <<<<<<< Conflict 1 of 1
     +++++++ Contents of side #1
     side
-    %%%%%%% Changes from base #1 to side #2 [-noeol]
+    %%%%%%% Changes from base #1 to side #2 (adds terminating newline)
      add newline
     -line
     +line
-    %%%%%%% Changes from base #2 to side #3 [+noeol]
+    %%%%%%% Changes from base #2 to side #3 (removes terminating newline)
      remove newline
     -line
     +line
-    %%%%%%% Changes from base #3 to side #4 [noeol]
+    %%%%%%% Changes from base #3 to side #4 (no terminating newline)
      no newline
     -line 1
     +line 2
@@ -2253,7 +2253,7 @@ fn test_update_conflict_from_content_only_no_eol_change() {
         @r##"
     line 1
     <<<<<<< Conflict 1 of 1
-    %%%%%%% Changes from base to side #1 [+noeol]
+    %%%%%%% Changes from base to side #1 (removes terminating newline)
     +line 2
     +++++++ Contents of side #2
     line 2