feat: Add compile_fail doctests

src/span.rs

@@ -40,6 +40,42 @@
 /// let span = span!(style; "test {:04}", 123);
 /// ```
 ///
+/// # Note
+///
+/// The first parameter must be a formatting specifier followed by a comma OR a [`Style`] followed by a semicolon.
+///
+/// For example, the following will fail to compile:
+///
+/// ```compile_fail
+/// # use ratatui::prelude::*;
+/// use ratatui_macros::span;
+/// let span = span!(Modifier::BOLD, "hello world");
+/// ```
+///
+/// But this will work:
+///
+/// ```rust
+/// # use ratatui::prelude::*;
+/// use ratatui_macros::span;
+/// let span = span!(Modifier::BOLD; "hello world");
+/// ```
+///
+/// The following will fail to compile:
+///
+/// ```compile_fail
+/// # use ratatui::prelude::*;
+/// use ratatui_macros::span;
+/// let span = span!("hello", "world");
+/// ```
+///
+/// But this will work:
+///
+/// ```rust
+/// # use ratatui::prelude::*;
+/// use ratatui_macros::span;
+/// let span = span!("hello {}", "world");
+/// ```
+///
 /// [`Color`]: crate::style::Color
 /// [`Style`]: crate::style::Style
 /// [`Span`]: crate::text::Span
@@ -53,7 +89,7 @@ macro_rules! span {
         ratatui::text::Span::raw(format!($string, $($arg)*))
     };
     ($style:expr, $($arg:tt)*) => {
-        compile_error!("first parameter must be a formatting specifier followed by a comma OR a `Style` followed by a semi-colon")
+        compile_error!("first parameter must be a formatting specifier followed by a comma OR a `Style` followed by a semicolon")
     };
     ($style:expr; $($arg:tt)*) => {
         ratatui::text::Span::styled(format!($($arg)*), $style)

tests/ui/fails.stderr

@@ -35,7 +35,7 @@ note: while trying to match `%`
    |     (== $token:tt %) => {
    |                   ^
 
-error: first parameter must be a formatting specifier followed by a comma OR a `Style` followed by a semi-colon
+error: first parameter must be a formatting specifier followed by a comma OR a `Style` followed by a semicolon
   --> tests/ui/fails.rs:17:13
    |
 17 |     let _ = span!(Modifier::BOLD, "hello world");