Proposal: Improved CoqIDE find/replace functionality

[jfehrle]

The current find/replace functionality is awkward to use and is, I think, dated.

The main change is to put the search parameters in a hidable subpanel in a more compact format at the top of editor panels. Find and replace would have separate function keys, say CTRL F and CTRL R. Fields for replace appear only when replace is requested.

I would drop detachability of the subpanel: I think it's not that helpful nor easy to use. The detached dialog is not visually tied to the editor window, hence more work for the user to match the dialog to the right editor panel. Currently, it's possible to use the dialog to replace text in an editor window even when it's not visible--likely confusing.

I also want to make the user experience more seamless:

• Highlighting text in the editor followed by CTRL F/R searches for that text
• Remembering the last search string
• Perhaps highlighting matches in the buffer
• Perhaps showing the number of matches

The Navigation menu has a separate search feature "Next"/"Prev" that appears to search for the word at the point of the cursor. I suggest we drop this duplicate feature.

Below is a rough idea of what this might look like for find and for replace (images adapted from other IDE software). The icons represent, from left to right (and skipping a few): case-sensitive, regex match, previous, next.

Let me know your thoughts.

The current CoqIDE find/replace panel for comparison: