This change simplifys UI code that uses the Frame type. E.g.:
```rust
fn draw<B: Backend>(frame: &mut Frame<B>) {
// ...
}
```
Frame was generic over Backend because it stored a reference to the
terminal in the field. Instead it now directly stores the viewport area
and current buffer. These are provided at creation time and are valid
for the duration of the frame.
BREAKING CHANGE: Frame is no longer generic over Backend. Code that
accepted `Frame<Backend>` will now need to accept `Frame`. To migrate
existing code, remove any generic parameters from code that uses an
instance of a Frame. E.g. the above code becomes:
```rust
fn draw(frame: &mut Frame) {
// ...
}
```
This helps to keep the prelude small and less likely to conflict with
other crates.
- remove widgets module from prelude as the entire module can be just as
easily imported with `use ratatui::widgets::*;`
- move prelude module into its own file
- update examples to import widgets module instead of just prelude
- added several modules to prelude to make it possible to qualify
imports that collide with other types that have similar names
* refactor: add Line type to replace Spans
`Line` is a significantly better name over `Spans` as the plural causes
confusion and the type really is a representation of a line of text made
up of spans.
This is a backwards compatible version of the approach from
https://github.com/tui-rs-revival/ratatui/pull/175
There is a significant amount of code that uses the Spans type and
methods, so instead of just renaming it, we add a new type and replace
parameters that accepts a `Spans` with a parameter that accepts
`Into<Line>`.
Note that the examples have been intentionally left using `Spans` in
this commit to demonstrate the compiler warnings that will be emitted in
existing code.
Implementation notes:
- moves the Spans code to text::spans and publicly reexports on the text
module. This makes the test in that module only relevant to the Spans
type.
- adds a line module with a copy of the code and tests from Spans with a
single addition: `impl<'a> From<Spans<'a>> for Line<'a>`
- adds tests for `Spans` (created and checked before refactoring)
- adds the same tests for `Line`
- updates all widget methods that accept and store Spans to instead
store `Line` and accept `Into<Line>`
* refactor: move text::Masked to text::masked::Masked
Re-exports the Masked type at text::Masked
* refactor: replace Spans with Line in tests/examples/docs
