docs(ast): discipline comments per comment spec

src/ast/expr.rs

@@ -174,14 +174,12 @@ pub struct FnCall {
     pub vals: RightValList,
 }
 
-/// Implementation of helper methods for function calls.
 impl FnCall {
     /// Returns the fully-qualified function name, including the module prefix
     /// if one is present (e.g., `"io::print"`), or just the bare function
     /// name otherwise (e.g., `"print"`).
     pub fn qualified_name(&self) -> String {
         if let Some(module) = &self.module_prefix {
-            // Combine module prefix and function name with `::` separator.
             format!("{module}::{}", self.name)
         } else {
             self.name.clone()

src/ast/types.rs

@@ -4,7 +4,7 @@
 //! nodes that appear in variable declarations, function parameters, and
 //! return-type annotations.
 
-/// Byte offset (or character index) into the source text.
+/// Byte offset into the source text.
 /// Used to track where each AST node originated for error reporting.
 pub type Pos = usize;