Comment wording cleanups.

lib/cretonne/meta/base/settings.py

@@ -1,7 +1,7 @@
 """
 Cretonne shared settings.
 
-This module defines settings are are relevant for all code generators.
+This module defines settings relevant for all code generators.
 """
 from __future__ import absolute_import
 from cdsl.settings import SettingGroup, BoolSetting, EnumSetting

lib/cretonne/meta/gen_instr.py

@@ -451,8 +451,8 @@ def gen_type_constraints(fmt, instrs):
 def gen_format_constructor(iform, fmt):
     # type: (InstructionFormat, srcgen.Formatter) -> None
     """
-    Emit a method for creating and inserting inserting an `iform` instruction,
-    where `iform` is an instruction format.
+    Emit a method for creating and inserting an `iform` instruction, where
+    `iform` is an instruction format.
 
     All instruction formats take an `opcode` argument and a `ctrl_typevar`
     argument for deducing the result types.

lib/cretonne/src/ir/layout.rs

@@ -1017,14 +1017,14 @@ pub trait CursorBase {
     /// - If the cursor points to the top of an EBB, the new EBB is inserted above the current one.
     /// - If the cursor is not pointing at anything, the new EBB is placed last in the layout.
     ///
-    /// This means that is is always valid to call this method, and it always leaves the cursor in
+    /// This means that it is always valid to call this method, and it always leaves the cursor in
     /// a state that will insert instructions into the new EBB.
     fn insert_ebb(&mut self, new_ebb: Ebb) {
         use self::CursorPosition::*;
         match self.position() {
             At(inst) => {
                 self.layout_mut().split_ebb(new_ebb, inst);
-                // All other cases move to `After(ebb)`, but in this case we we'll stay `At(inst)`.
+                // All other cases move to `After(ebb)`, but in this case we'll stay `At(inst)`.
                 return;
             }
             Nowhere => self.layout_mut().append_ebb(new_ebb),