Fix template generation to preserve statements when adding before/after coordinates

[JohannisK]

What's changed?

This PR fixes an issue where the template generator incorrectly modified statements when using JavaCoordinates to add statements before or after existing code, rather than replacing them.

What's your motivation?

When using JavaTemplate to add a statement before an existing method invocation (e.g., using firstStatement() coordinates), the template generator would incorrectly prefix the new statement with variable declarations like Object o =. This happened because the generator didn't distinguish between REPLACEMENT mode (where such prefixes ensure valid compilation) and addition modes (BEFORE/AFTER) where the statement should remain unmodified.

For example, when adding String newLine = "test"; before o.get();, the generator would produce the invalid statement: Object o = String newLine = "test";

Solution

• Added the JavaCoordinates.Mode parameter to the contextFreeTemplate method signature
• Modified template generation logic to only add variable declaration prefixes when in REPLACEMENT mode
• Applied the fix consistently across Java, Groovy, and Kotlin template generators

[github-actions]

Some suggestions could not be made:

• rewrite-gradle/src/main/java/org/openrewrite/gradle/marker/GradleDependencyConfiguration.java
  • lines 26-26

[github-actions]

Some suggestions could not be made:

• rewrite-gradle/src/main/java/org/openrewrite/gradle/marker/GradleDependencyConfiguration.java
  • lines 26-26

[knutwannheden]

As discussed with @JohannisK we want to explore a different approach, as it doesn't seem quite right to link this behavior to the mode.