doc: remove duplicate words. Thanks, Matt Might!

doc/rust.md

@@ -46,7 +46,7 @@ keep the size and complexity of the language under control.
 very incomplete; only a modest number of sections have accompanying grammar
 rules. Formalizing the grammar accepted by the Rust parser is ongoing work,
 but future versions of this document will contain a complete
-grammar. Moreover, we hope that this grammar will be be extracted and verified
+grammar. Moreover, we hope that this grammar will be extracted and verified
 as LL(1) by an automated grammar-analysis tool, and further tested against the
 Rust sources. Preliminary versions of this automation exist, but are not yet
 complete.
@@ -1450,7 +1450,7 @@ init : [ '=' | '<-' ] expr ;
 ~~~~~~~~
 
 
-A _slot declaration_ has one one of two forms:
+A _slot declaration_ has one of two forms:
 
 * `let` `pattern` `optional-init`;
 * `let` `pattern` : `type` `optional-init`;
@@ -2647,7 +2647,7 @@ The machine types are the following:
 #### Machine-dependent integer types
 
 The Rust type `uint`^[A Rust `uint` is analogous to a C99 `uintptr_t`.] is an
-unsigned integer type with with target-machine-dependent size. Its size, in
+unsigned integer type with target-machine-dependent size. Its size, in
 bits, is equal to the number of bits required to hold any memory address on
 the target machine.
 

doc/tutorial.md

@@ -2223,7 +2223,7 @@ native mod something {
 Most native C code use the cdecl calling convention, so that is what
 Rust uses by default when calling native functions. Some native functions,
 most notably the Windows API, use other calling conventions, so Rust
-provides a way to to hint to the compiler which is expected by using
+provides a way to hint to the compiler which is expected by using
 the `"abi"` attribute:
 
 ~~~~