shift+ctrl+alt+c (copy reference) on symbol copies file:line

**Is your feature request related to a problem? Please describe.**

With a editor view like:
```clj
(ns bar.foo)
(def aa 1)
(def b a|a); `|` denotes the cursor position and is not actually in the source code.
```

Press shift+ctrl+alt+c (or right click on `aa` in the 3rd line and choose "Copy / Paste Special > Copy Reference") and paste your clipboard somewhere. Notice that `file:line` (`bar/foo.clj:3`, i.e. not even the `file:line` where the symbol is defined, but the `file:line` where the cursor is currently) was copied and not the fully qualified symbol name (`bar.foo/aa`) as you might expect from e.g. Cursive.

**Describe the solution you'd like**

The Copy Reference action copies the fully qualified name `bar.foo/aa` of the symbol under the cursor.

**Describe alternatives you've considered**

Navigate to the symbol definition (ctrl+click) to collect the `name` bit, navigate to the top of the file to collect the `namespace` bit, assemble the fully qualified symbol name from the two manually.