fix formatting for BUNDLE_PREFER_PATCH variable in man page

Author: toy

bundler/lib/bundler/man/bundle-config.1

@@ -172,7 +172,7 @@ Whether Bundler will install gems into the default system path (\fBGem\.dir\fR)\
 \fBplugins\fR (\fBBUNDLE_PLUGINS\fR)
 Enable Bundler's experimental plugin system\.
 .TP
-\fBprefer_patch\fR (BUNDLE_PREFER_PATCH)
+\fBprefer_patch\fR (\fBBUNDLE_PREFER_PATCH\fR)
 Prefer updating only to next patch version during updates\. Makes \fBbundle update\fR calls equivalent to \fBbundler update \-\-patch\fR\.
 .TP
 \fBredirect\fR (\fBBUNDLE_REDIRECT\fR)

bundler/lib/bundler/man/bundle-config.1.ronn

@@ -223,7 +223,7 @@ learn more about their operation in [bundle install(1)](bundle-install.1.html).
    Whether Bundler will install gems into the default system path (`Gem.dir`).
 * `plugins` (`BUNDLE_PLUGINS`):
    Enable Bundler's experimental plugin system.
-* `prefer_patch` (BUNDLE_PREFER_PATCH):
+* `prefer_patch` (`BUNDLE_PREFER_PATCH`):
    Prefer updating only to next patch version during updates. Makes `bundle update` calls equivalent to `bundler update --patch`.
 * `redirect` (`BUNDLE_REDIRECT`):
    The number of redirects allowed for network requests. Defaults to `5`.