Fix typos (#1151)

Found via following command:

    codespell -L crate,nin,numer,struc,ded,fo

src/format.rs

@@ -227,7 +227,7 @@ pub trait CenterRightNumbers {
     // these are now aligned to the center right by having this trait return " "
     // instead of "". This is prepended to the format string. In the case of " "
     // the trailing " " must then be removed so everything is shifted to the right.
-    // This asumes no special padding characters, i.e. the default of space.
+    // This assumes no special padding characters, i.e. the default of space.
     fn center_right_space(&self, alignment: Align, width: usize) -> &'static str;
 }
 

src/utils/process.rs

@@ -598,7 +598,7 @@ pub mod tests {
     // When calling `FakeParentArgs::get()`, it can return `Some(values)` which were set earlier
     // during in the #[test]. Otherwise returns None.
     // This value can be valid once: `FakeParentArgs::once(val)`, for the entire scope:
-    // `FakeParentArgs::for_scope(val)`, or can be different values everytime `get()` is called:
+    // `FakeParentArgs::for_scope(val)`, or can be different values every time `get()` is called:
     // `FakeParentArgs::with([val1, val2, val3])`.
     // It is an error if `once` or `with` values remain unused, or are overused.
     // Note: The values are stored per-thread, so the expectation is that no thread boundaries are
@@ -890,7 +890,7 @@ pub mod tests {
     fn test_process_testing_assert_never_used() {
         let _args = FakeParentArgs::once("never used");
 
-        // causes a panic while panicing, so can't test:
+        // causes a panic while panicking, so can't test:
         // let _args = FakeParentArgs::for_scope(&"never used");
         // let _args = FakeParentArgs::once(&"never used");
     }
@@ -939,7 +939,7 @@ pub mod tests {
             calling_process_cmdline(ProcInfo::new(), guess_git_blame_filename_extension),
             Some("once".into())
         );
-        // ignored: dropping causes a panic while panicing, so can't test
+        // ignored: dropping causes a panic while panicking, so can't test
         calling_process_cmdline(ProcInfo::new(), guess_git_blame_filename_extension);
     }