Improve automatic :nohlsearch feature
Handle auto :nohlsearch for visual and operator-pending
doc: auto :nohlsearch feature
The number of nest can now be specified
Support auto nohlsearch for stay motion
Fix mappings name noh -> nohl
spec: test for automatic nohlsearch feature
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You cannot fire :nohlsearch with InsertEnter event because of feedkeys()
doc: write description of auto :nohlsearch on README
Merge branch 'auto-nohlsearch' into dev