Deprecate, don't remove

This makes it ever so slightly easier for users upgrading to 2.0. We still remove all functionality from the flag - it now no-ops.

src/python/pants/option/global_options.py

@@ -218,6 +218,21 @@ def register_bootstrap_options(cls, register):
             "from the start of the warning string, and will always be case-insensitive. "
             "See the `warnings` module documentation for more background on these are used.",
         )
+        register(
+            "--option-name-check-distance",
+            advanced=True,
+            type=int,
+            default=2,
+            help=(
+                "The maximum Levenshtein distance to use when offering suggestions for invalid "
+                "option names."
+            ),
+            removal_version="2.1.0.dev0",
+            removal_hint=(
+                "The option `--option-name-check-distance` no longer does anything, as Pants now "
+                "always uses the default of 2."
+            ),
+        )
 
         register(
             "--pants-version",