fix: Fix unused-variable reported on variable names starting with digit (#1689)

Author: bhirsz

src/robocop/linter/rules/misc.py

@@ -1610,7 +1610,7 @@ def find_not_nested_variable(self, value: str, can_be_escaped: bool) -> None:
                 elif value[i] == "}":
                     depth -= 1
                     if depth == 0:
-                        self.update_used_variables(value[start_pos : i + 1])
+                        self.update_used_variables(value[start_pos + 2 : i])
                         full_match = start_pos == 0 and i + 1 == len(value)
                         break
 

tests/linter/rules/variables/unused_variable/unused_section_vars.robot

@@ -37,6 +37,7 @@ ${METADATA_VALUE}    value
 @{TEMPLATE_ARGS}    arg1   arg2
 ${VAR_DOCUMENTATION}    Documentation value
 ${VAR_TAG}              Tag value
+${3MAR_DESCRIPTION}     Lorem ipsum 2
 
 
 *** Test Cases ****
@@ -67,3 +68,6 @@ Keyword
 Keyword With Arguments
     [Arguments]    ${arg}=${USED_IN_ARG_DEFAULT}    ${arg2}=value with ${USED_IN_ARG_DEFAULT2}
     No Operation
+
+Use Variable With Numbers
+    Log To Console    ${3MAR_DESCRIPTION}