Add some documentation

core/src/lib.rs

@@ -1,2 +1,2 @@
 mod text_buffer;
-pub use text_buffer::{TextBuffer, TextBufferReader, TextBufferWriter};
+pub use text_buffer::{Point, TextBuffer, TextBufferReader, TextBufferWriter};

core/src/text_buffer/mod.rs

@@ -10,29 +10,36 @@ pub use reader::TextBufferReader;
 mod writer;
 pub use writer::TextBufferWriter;
 
+/// A block of text, usually containing the contents of a text file.
 pub struct TextBuffer {
     contents: Rc<Rope>,
 }
 
+/// A location in a [TextBuffer]
 pub enum Point {
+    /// The end of the buffer
     End,
 }
 
 impl TextBuffer {
+    /// Create a new empty [TextBuffer]
     pub fn new() -> Self {
         Self {
             contents: Rope::empty(),
         }
     }
 
+    /// The size of the contents in bytes
     pub fn num_bytes(&self) -> usize {
         self.contents.total_bytes()
     }
 
+    /// The size of the contents in characters
     pub fn num_chars(&self) -> usize {
         self.contents.total_chars()
     }
 
+    /// The total number of lines in the contents
     pub fn num_lines(&self) -> usize {
         let num_chars = self.num_chars();
         if num_chars == 0 {
@@ -51,6 +58,7 @@ impl TextBuffer {
         }
     }
 
+    /// Insert `text` at `point`.
     pub fn insert_text(&mut self, text: impl Into<String>, point: Point) {
         match point {
             Point::End => {