Mentions countLines() may return unexpected values.
Homogenizes docstrings for strutils module.

This mostly involves separating the short description string from the
full description block, capitalizing it, and adding any worthwhile
hyperlinks to other symbols.
Merge pull request #1372 from gradha/pr_strutils_docstrings

Improvements to strutils docstrings
sequtils: Correct documentation for keepIf proc
sequtils: Complete mapIt documentation example
Update nimrod.ini
Merge pull request #1378 from sjakobi/patch-2

sequtils: Complete mapIt documentation example
Merge pull request #1377 from sjakobi/patch-1

sequtils: Correct documentation for keepIf proc
Fixes #1219.
Fixes #1065.