When mouse pointer is mapped to character position, the algorithm
rounds the position to the nearest left edge of a character. This makes
sense for selections, but not for hotspots like links, where "character
under the pointer" is better solution. This patch adds edge mode as an
option to getCharacterPosition and disables it for hotspots.

• Turn on "Underline links" option (Profile options → Mouse)
• Increase font size in Konsole so it will be easy to move mouse pointer above left or right half of the character
• Run: echo -e 'www.kde.org\033[31;41m \033[0m'
• Place pointer on the right half of the 'g' character

Expected result: underline should have the same color as the link
Actual result: underline uses color from the next character on the right