Fix for Issue #3942: [quick edit] in HTML file, quick editor shows function found from other file, not one in current file

The Jump-To-Definition part of the search was finding the function in the .html file, but
the following part of the search -- the old QuickEdit search -- only looked in .js files.
Code review -- simplify changes.  Added flag to findMatchingFunctions() instead
of duplicating most of it.
Added comment to document new @param.
Code review tweaks.
Merge pull request #4120 from jeffkenton/quiickedit

Fix for Issue #3942: QuickEdit ignoring .html files