[FIX] base: correct Lesotho's currency symbol

The Lesotho Loti has the symbol M and not L
Example of use:
http://lestimes.com/businessman-xie-in-m27-million-scandal/
http://lra.org.ls/sites/default/files/2020-10/LRA%20Integrated%20Annual%20Report%202019.pdf



Fixes odoo/odoo#62807

closes odoo/odoo#65644

X-original-commit: f6b55a46
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

odoo/addons/base/data/res_currency_data.xml

@@ -908,7 +908,7 @@
 
         <record id="LSL" model="res.currency">
             <field name="name">LSL</field>
-            <field name="symbol">L</field>
+            <field name="symbol">M</field>
             <field name="rounding">0.01</field>
             <field name="active" eval="False"/>
             <field name="currency_unit_label">Loti</field>