gitweb: Clean up code in git_search_* subroutines

gitweb: Clean up code in git_search_* subroutines

Replace sequence of

       $foo .= "bar";
       $foo .= "baz";

with

       $foo .= "bar" .
	       "baz";

Use href(-replay=>1, -page=>undef) for first page of a multipl-page view.

Wrap some lines to reduce their length. Some lines still have more than 80
characters, but lines are shorter now.

No functional changes intended.

Signed-off-by: Jakub Narebski <redacted>
Signed-off-by: Junio C Hamano <redacted>