[Docs] Clarify the scaled histogram comments slightly

Among other things, correct a typo: "reminder" -> "remainder".

R=mpearson@chromium.org

Bug: None
Change-Id: Ic8f35a7024e7cb18128a05b043b37b866abc65e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1729797
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Mark Pearson <mpearson@chromium.org>
Auto-Submit: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682928}

base/metrics/histogram_macros.h

@@ -126,11 +126,13 @@
   UMA_HISTOGRAM_EXACT_LINEAR(name, percent_as_int, 101)
 
 //------------------------------------------------------------------------------
-// Scaled Linear histograms.
+// Scaled linear histograms.
 
 // These take |count| and |scale| parameters to allow cumulative reporting of
-// large numbers. Only the scaled count is reported but the reminder is kept so
-// multiple calls will accumulate correctly.  Only "exact linear" is supported.
+// large numbers. For example, code might pass a count of 1825 bytes and a scale
+// of 1024 bytes to report values in kilobytes. Only the scaled count is
+// reported, but the remainder is tracked between calls, so that multiple calls
+// will accumulate correctly. Only "exact linear" is supported.
 // It'll be necessary to #include "base/lazy_instance.h" to use this macro.
 
 #define UMA_HISTOGRAM_SCALED_EXACT_LINEAR(name, sample, count, value_max, \