twitter/bootstrap — pull request #2556 by brodkin (2012-03-13 16:25:22+00:00)
Title: Fix alignment of pre/appended form controls in v2.0.2

Form inputs at line 62 are given a 9px bottom margin in forms.less.
Prepended and appended inputs need their add-on to have a matching 9px
bottom margin for proper alignment when using align: middle.

Alternatively, add-on and input's margins could be zeroed when contained by input-prepend and input-prepend could take on the margin.