Added "mu" and "mc" prefixes.

CHANGES

@@ -4,6 +4,7 @@ Pint Changelog
 0.25 (unreleased)
 -----------------
 
+- Added mu and mc as alternatives for SI micro prefix
 - Added ℓ as alternative for liter
 - Support permille units and `‰` symbol (PR #2033, Issue #1963)
 

pint/default_en.txt

@@ -72,7 +72,7 @@ pico- =  1e-12 = p-
 nano- =  1e-9  = n-
 # The micro (U+00B5) and Greek mu (U+03BC) are both valid prefixes,
 # and they often use the same glyph.
-micro- = 1e-6  = µ- = μ- = u-
+micro- = 1e-6  = µ- = μ- = u- = mu- = mc-
 milli- = 1e-3  = m-
 centi- = 1e-2  = c-
 deci- =  1e-1  = d-

pint/testsuite/conftest.py

@@ -14,7 +14,7 @@
 femto- = 1e-15 = f-
 pico- =  1e-12 = p-
 nano- =  1e-9  = n-
-micro- = 1e-6  = µ- = μ- = u-
+micro- = 1e-6  = µ- = μ- = u- = mu- = mc-
 milli- = 1e-3  = m-
 centi- = 1e-2  = c-
 deci- =  1e-1  = d-

pint/testsuite/test_issues.py

@@ -408,6 +408,12 @@ def test_micro_creation_U03bc(self, module_registry):
     def test_micro_creation_U00b5(self, module_registry):
         module_registry.Quantity(2, "µm")
 
+    def test_micro_creation_mu(self, module_registry):
+        module_registry.Quantity(2, "mug")
+
+    def test_micro_creation_mc(self, module_registry):
+        module_registry.Quantity(2, "mcg")
+
     def test_liter_creation_U2113(self, module_registry):
         module_registry.Quantity(2, "ℓ")