Feat: Accept Copilot Suggestion Up To Character (Find Motion Support)

**Summary:**
Requesting a feature to accept Copilot suggestions up to and including (`f` motion) or up to before (`t` motion) a specified character (i.e., leverage Vim’s `f` and `t` motions).

**Example:**
Given the suggestion:
```
The quick brown fox jumps over the lazy dog.
```
- Typing a key sequence like `fj` would accept and insert:
```
The quick brown fox j
```
(up to and including the first `j` in the suggestion).

- Typing a key sequence like `tj` would accept and insert:
```
The quick brown fox
```
(up to but not including the first `j` in the suggestion).

**Rationale:**
- Provides granular acceptance of suggestions.
- Mimics familiar Vim motions for efficiency.