crecord: new keys g & G to navigate to the top and bottom respectively This patch introduces two new keys 'g' and 'G' that helps to navigate to the top and bottom of the file/hunk/line respectively. This is inline with the shortcuts used in man, less, more and such tools that makes it convenient to navigate swiftly. 'g' or HOME navigates to the top most file in the ncurses window. 'G' or END navigates to the bottom most file/hunk/line depending on the whether the fold is active or not. If the bottom most file is folded, it navigates to that file and stops there. If the bottom most file is unfolded, it navigates to the bottom most hunk in that file and stops there. If the bottom most hunk is unfolded, it navigates to the bottom most line in that hunk. Differential Revision: https://phab.mercurial-scm.org/D6178