Remove dec of JCodeFile::buildMethodRegexString

In previous commits, the static function buildMethodRegexString
was moved from the JCodeFile function and placed into the JLine function.

Mistakenly, the header-file declaration of this function was not changed
accordingly, until this commit.  The unchanged declaration threw
errors when linking into an executable
Change visibility of JLine::buildMethodRegexString

The recently added buildMethodRegexString function was added as a
private static function.  This was a mistake, as the function was
intended to be publicly accessible.