help: set the large-file-limit to 10MB

This is a minor increase (5%) and makes the doc much clearer.

Differential Revision: https://phab.mercurial-scm.org/D12484

mercurial/configitems.py

@@ -2255,7 +2255,7 b' coreconfigitem('
 coreconfigitem(
     b'ui',
     b'large-file-limit',
-    default=10000000,
+    default=10 * (2 ** 20),
 )
 coreconfigitem(
     b'ui',

mercurial/helptext/config.txt

@@ -2631,7 +2631,7 b' User interface controls.'
     Largest file size that gives no memory use warning.
     Possible values are integers or 0 to disable the check.
     Value is expressed in bytes by default, one can use standard units for
-    convenience (e.g. 10MB, 0.1GB, etc) (default: 10000000)
+    convenience (e.g. 10MB, 0.1GB, etc) (default: 10MB)
 
 ``logtemplate``
     (DEPRECATED) Use ``command-templates.log`` instead.