docs: Give all tutorials consistent titles and intro sections

doc/tutorial-ffi.md

@@ -1,4 +1,6 @@
-# Interacting with foreign code
+% Rust Foreign Function Interface Tutorial
+
+# Introduction
 
 One of Rust's aims, as a system programming language, is to
 interoperate well with C code.
@@ -38,7 +40,7 @@ fn main(args: ~[~str]) {
 }
 ~~~~
 
-## Foreign modules
+# Foreign modules
 
 Before we can call `SHA1`, we have to declare it. That is what this
 part of the program is responsible for:
@@ -68,7 +70,7 @@ extern mod something {
 }
 ~~~~
 
-## Foreign calling conventions
+# Foreign calling conventions
 
 Most foreign code will be C code, which usually uses the `cdecl` calling
 convention, so that is what Rust uses by default when calling foreign
@@ -88,7 +90,7 @@ The `"abi"` attribute applies to a foreign module (it can not be applied
 to a single function within a module), and must be either `"cdecl"`
 or `"stdcall"`. Other conventions may be defined in the future.
 
-## Unsafe pointers
+# Unsafe pointers
 
 The foreign `SHA1` function is declared to take three arguments, and
 return a pointer.
@@ -118,7 +120,7 @@ caution—unlike Rust's other pointer types, unsafe pointers are
 completely unmanaged, so they might point at invalid memory, or be
 null pointers.
 
-## Unsafe blocks
+# Unsafe blocks
 
 The `sha1` function is the most obscure part of the program.
 
@@ -159,7 +161,7 @@ unsafe fn kaboom() { ~"I'm harmless!"; }
 This function can only be called from an unsafe block or another
 unsafe function.
 
-## Pointer fiddling
+# Pointer fiddling
 
 The standard library defines a number of helper functions for dealing
 with unsafe data, casting between types, and generally subverting
@@ -202,7 +204,7 @@ unsafe pointer that was returned by `SHA1`. SHA1 digests are always
 twenty bytes long, so we can pass `20u` for the length of the new
 vector.
 
-## Passing structures
+# Passing structures
 
 C functions often take pointers to structs as arguments. Since Rust
 structs are binary-compatible with C structs, Rust programs can call

doc/tutorial-macros.md

@@ -1,4 +1,6 @@
-# Macros
+% Rust Macros Tutorial
+
+# Introduction
 
 Functions are the programmer's primary tool of abstraction, but there are
 cases in which they are insufficient, because the programmer wants to
@@ -50,7 +52,7 @@ early_return!(input_2 special_b);
 
 Macros are defined in pattern-matching style:
 
-## Invocation syntax
+# Invocation syntax
 
 On the left-hand-side of the `=>` is the macro invocation syntax. It is
 free-form, excepting the following rules:
@@ -69,7 +71,7 @@ rules of tokenization apply,
 So `($x:ident => (($e:expr)))`, though excessively fancy, would create a macro
 that could be invoked like `my_macro!(i=>(( 2+2 )))`.
 
-## Transcription syntax
+# Transcription syntax
 
 The right-hand side of the `=>` follows the same rules as the left-hand side,
 except that `$` need only be followed by the name of the syntactic fragment
@@ -80,9 +82,9 @@ an expression; currently, user-defined macros can only be invoked in
 expression position (even though `macro_rules!` itself can be in item
 position).
 
-## Multiplicity
+# Multiplicity
 
-### Invocation
+## Invocation
 
 Going back to the motivating example, suppose that we wanted each invocation
 of `early_return` to potentially accept multiple "special" identifiers. The

doc/tutorial-tasks.md

@@ -1,4 +1,6 @@
-% Tasks and communication in Rust
+% Rust Tasks and Communication Tutorial
+
+# Introduction
 
 Rust supports a system of lightweight tasks, similar to what is found
 in Erlang or other actor systems. Rust tasks communicate via messages