typing: remove unused DependencyType

mesonbuild/dependencies/__init__.py

@@ -216,7 +216,7 @@ this approach, and no new dependencies should do this.
 # of:
 # - An ExternalDependency subclass
 # - A DependencyFactory object
-# - A callable with a signature of (Environment, MachineChoice, Dict[str, Any]) -> List[Callable[[], DependencyType]]
+# - A callable with a signature of (Environment, MachineChoice, Dict[str, Any]) -> List[Callable[[], ExternalDependency]]
 packages.update({
     # From dev:
     'gtest': gtest_factory,

mesonbuild/dependencies/base.py

@@ -30,7 +30,7 @@ if T.TYPE_CHECKING:
     from ..compilers.compilers import Compiler
     from ..environment import Environment
     from ..build import BuildTarget
-    DependencyType = T.TypeVar('DependencyType', bound='Dependency')
+    from ..mesonlib import FileOrString
 
 
 class DependencyException(MesonException):