Merge #8524 #8527

8524: Fix extract function with partial block selection r=matklad a=brandondong

**Reproduction:**
```rust
fn foo() {
    let n = 1;
    let mut v = $0n * n;$0
    v += 1;
}
```
1. Select the snippet ($0) and use the "Extract into function" assist.
2. Extracted function is incorrect and does not compile:
```rust
fn foo() {
    let n = 1;
    let mut v = fun_name(n);
    v += 1;
}

fn fun_name(n: i32) {}
```
3. Omitting the ending semicolon from the selection fixes the extracted function:
```rust
fn fun_name(n: i32) -> i32 {
    n * n
}
```

**Cause:**
- When `extraction_target` uses a block extraction (semicolon case) instead of an expression extraction (no semicolon case), the user selection is directly used as the TextRange.
- However, the existing function extraction logic for blocks requires that the TextRange spans from start to end of complete statements to work correctly.
- For example:
```rust
fn foo() {
    let m = 2;
    let n = 1;
    let mut v = m $0* n;
    let mut w = 3;$0
    v += 1;
    w += 1;
}
```
produces
```rust
fn foo() {
    let m = 2;
    let n = 1;
    let mut v = m let mut w = fun_name(n);
    v += 1;
    w += 1;
}

fn fun_name(n: i32) -> i32 {
    let mut w = 3;
    w
}
```
- The user selected TextRange is directly replaced by the function call which is now in the middle of another statement. The extracted function body only contains statements that were fully covered by the TextRange and so the `* n` code is deleted. The logic for calculating variable usage and outlived variables for the function parameters and return type respectively search within the TextRange and so do not include `m` or `v`.

**Fix:**
- Only extract full statements when using block extraction. If a user selected part of a statement, extract that full statement.

8527: Switch introduce_named_lifetime assist to use mutable syntax tree  r=matklad a=iDawer

This extends `GenericParamsOwnerEdit` trait with `get_or_create_generic_param_list` method

Co-authored-by: Brandon <[email protected]>
Co-authored-by: Dawer <[email protected]>