chalk help validcommand --valid-flag shouldn't search docs

[ee7]

Example

Run with latest chalk release (v0.3.3) or commit (cf9ebf8):

chalk help insert --no-color

Expected behavior

Prints the help for insert without color, which is what chalk insert --help --no-color does.

Observed behavior

Prints the results of a documentation search for insert and --no-color:

Searching Documentation For Terms: Insert, --No-Color
[large amount of output]

Other examples

chalk help commands --no-pager

Related issues

This is similar to #172