Make prompts and i-searches the same word length

`(reverse-i-search)` and `(i-search)` are different length prompts and so when switching search directions, the entire line shifts position.  I find it disorienting.  Fortunately, `reverse` and `forward` both have seven characters.  This very very minimal patch renames (i-search) to (forward-i-search).  It isn't how readline behaves, but I think it is better.

Similarly, `"help> "` becomes `" help> "` to keep the prompt start at the same location.
Add region-based findmin and findmax (closes #6716)
better handling of empty file in readdlm.
fixes #6898
Merge pull request #6893 from mbauman/stable-repl-prompt

Make prompts and i-searches the same word length
add complex log1p (fix #3141)
doc: typo in output
Merge pull request #6894 from JuliaLang/teh/findminmax

Add region-based findmin and findmax (closes #6716)
faster and more compact serialization of symbols and strings
Set function performance: build up sets instead of copying and deleting
Merge pull request #6904 from stevengj/log1p

add complex log1p
Merge pull request #6905 from simonbyrne/patch-1

doc: typo in output
Merge pull request #6902 from tanmaykm/readcsv

better handling of empty file in readdlm.