Keep module docs as one string.

src/api/compile.rs

@@ -2,7 +2,6 @@
 
 use crate::parser::{ParseResult, ParseState};
 use crate::{Engine, OptimizationLevel, Scope, AST};
-use std::mem;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -225,9 +224,7 @@ impl Engine {
         let mut state = ParseState::new(self, scope, tokenizer_control);
         let mut ast = self.parse(&mut stream.peekable(), &mut state, optimization_level)?;
         #[cfg(feature = "metadata")]
-        ast.set_doc(mem::take(
-            &mut state.tokenizer_control.borrow_mut().global_comments,
-        ));
+        ast.set_doc(state.tokenizer_control.borrow().global_comments.join("\n"));
         Ok(ast)
     }
     /// Compile a string containing an expression into an [`AST`],