Add version attributes up_to_1, up_to_2, up_to_3 (#38410)

Making them also available in spec format string

lib/spack/docs/module_file_support.rst

@@ -456,14 +456,13 @@ For instance, the following config options,
        tcl:
          all:
            suffixes:
-             ^python@3: 'python{^python.version}'
+             ^python@3: 'python{^python.version.up_to_2}'
              ^openblas: 'openblas'
 
-will add a ``python-3.12.1`` version string to any packages compiled with
-Python matching the spec, ``python@3``. This is useful to know which
-version of Python a set of Python extensions is associated with. Likewise, the
-``openblas`` string is attached to any program that has openblas in the spec,
-most likely via the ``+blas`` variant specification.
+will add a ``python3.12`` to module names of packages compiled with Python 3.12, and similarly for
+all specs depending on ``python@3``. This is useful to know which version of Python a set of Python
+extensions is associated with. Likewise, the ``openblas`` string is attached to any program that
+has openblas in the spec, most likely via the ``+blas`` variant specification.
 
 The most heavyweight solution to module naming is to change the entire
 naming convention for module files. This uses the projections format

lib/spack/spack/test/spec_semantics.py

@@ -869,6 +869,12 @@ def test_spec_formatting(self, default_mock_concretization):
             ("{namespace=namespace}", "namespace=", "namespace", lambda spec: spec),
             ("{compiler.name}", "", "name", lambda spec: spec.compiler),
             ("{compiler.version}", "", "version", lambda spec: spec.compiler),
+            (
+                "{compiler.version.up_to_1}",
+                "",
+                "up_to_1",
+                lambda spec: spec.compiler.version.up_to(1),
+            ),
             ("{%compiler.name}", "%", "name", lambda spec: spec.compiler),
             ("{@compiler.version}", "@", "version", lambda spec: spec.compiler),
             ("{architecture.platform}", "", "platform", lambda spec: spec.architecture),

lib/spack/spack/version/version_types.py

@@ -490,6 +490,21 @@ def up_to(self, index: int) -> "StandardVersion":
         """
         return self[:index]
 
+    @property
+    def up_to_1(self):
+        """The version truncated to the first component."""
+        return self.up_to(1)
+
+    @property
+    def up_to_2(self):
+        """The version truncated to the first two components."""
+        return self.up_to(2)
+
+    @property
+    def up_to_3(self):
+        """The version truncated to the first three components."""
+        return self.up_to(3)
+
 
 _STANDARD_VERSION_TYPEMIN = StandardVersion("", ((), (ALPHA,)), ("",))