refactor(buffer): deprecate assert_buffer_eq! in favor of assert_eq! (#…

…1007)

- Simplify `assert_buffer_eq!` logic.
- Deprecate `assert_buffer_eq!`.
- Introduce `TestBackend::assert_buffer_lines`.

Also simplify many tests involving buffer comparisons.

For the deprecation, just use `assert_eq` instead of `assert_buffer_eq`:

```diff
-assert_buffer_eq!(actual, expected);
+assert_eq!(actual, expected);
```

---

I noticed `assert_buffer_eq!` creating no test coverage reports and
looked into this macro. First I simplified it. Then I noticed a bunch of
`assert_eq!(buffer, …)` and other indirect usages of this macro (like
`TestBackend::assert_buffer`).

The good thing here is that it's mainly used in tests so not many
changes to the library code.

Cargo.toml

@@ -30,16 +30,15 @@ cassowary = "0.3"
 compact_str = "0.7.1"
 crossterm = { version = "0.27", optional = true }
 document-features = { version = "0.2.7", optional = true }
-indoc = "2.0"
 itertools = "0.12"
 lru = "0.12.0"
 paste = "1.0.2"
 serde = { version = "1", optional = true, features = ["derive"] }
 stability = "0.2.0"
 strum = { version = "0.26", features = ["derive"] }
-time = { version = "0.3.11", optional = true, features = ["local-offset"] }
 termion = { version = "3.0", optional = true }
 termwiz = { version = "0.22.0", optional = true }
+time = { version = "0.3.11", optional = true, features = ["local-offset"] }
 unicode-segmentation = "1.10"
 unicode-truncate = "1"
 unicode-width = "0.1"
@@ -56,6 +55,7 @@ criterion = { version = "0.5.1", features = ["html_reports"] }
 derive_builder = "0.20.0"
 fakeit = "1.1"
 font8x8 = "0.3.1"
+indoc = "2"
 palette = "0.7.3"
 pretty_assertions = "1.4.0"
 rand = "0.8.5"

examples/barchart.rs

@@ -286,10 +286,10 @@ fn draw_legend(f: &mut Frame, area: Rect) {
             "- Company B",
             Style::default().fg(Color::Yellow),
         )),
-        Line::from(vec![Span::styled(
+        Line::from(Span::styled(
             "- Company C",
             Style::default().fg(Color::White),
-        )]),
+        )),
     ];
 
     let block = Block::bordered().style(Style::default().fg(Color::White));