Remove double spaces after dots in comments

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -20,7 +20,7 @@ pub fn expand_deriving_clone(
     // some additional `AssertParamIsClone` assertions.
     //
     // We can use the simple form if either of the following are true.
-    // - The type derives Copy and there are no generic parameters.  (If we
+    // - The type derives Copy and there are no generic parameters. (If we
     //   used the simple form with generics, we'd have to bound the generics
     //   with Clone + Copy, and then there'd be no Clone impl at all if the
     //   user fills in something that is Clone but not Copy. After

compiler/rustc_builtin_macros/src/env.rs

@@ -1,4 +1,4 @@
-// The compiler code necessary to support the env! extension.  Eventually this
+// The compiler code necessary to support the env! extension. Eventually this
 // should all get sucked into either the compiler syntax extension plugin
 // interface.
 //

compiler/rustc_builtin_macros/src/format.rs

@@ -583,7 +583,7 @@ fn report_missing_placeholders(
     if detect_foreign_fmt {
         use super::format_foreign as foreign;
 
-        // The set of foreign substitutions we've explained.  This prevents spamming the user
+        // The set of foreign substitutions we've explained. This prevents spamming the user
         // with `%d should be written as {}` over and over again.
         let mut explained = FxHashSet::default();
 

compiler/rustc_builtin_macros/src/format_foreign.rs

@@ -253,7 +253,7 @@ pub(crate) mod printf {
     #[derive(Copy, Clone, PartialEq, Debug)]
     pub enum Num {
         // The range of these values is technically bounded by `NL_ARGMAX`... but, at least for GNU
-        // libc, it apparently has no real fixed limit.  A `u16` is used here on the basis that it
+        // libc, it apparently has no real fixed limit. A `u16` is used here on the basis that it
         // is *vanishingly* unlikely that *anyone* is going to try formatting something wider, or
         // with more precision, than 32 thousand positions which is so wide it couldn't possibly fit
         // on a screen.