Split [.foo] into [.][foo] when parsing test specs

b77cec05c0 fixed this problem for tagging tests, so that a test
case tagged with `[.foo]` would be parsed as tagged with `[.][foo]`.
This does the same for the test spec parsing.

Fixes #1798

src/catch2/catch_test_spec_parser.h

@@ -54,28 +54,12 @@ namespace Catch {
         void addFilter();
         bool separate();
 
-        template<typename T>
-        void addPattern() {
-            std::string token = m_patternName;
-            for( std::size_t i = 0; i < m_escapeChars.size(); ++i )
-                token = token.substr( 0, m_escapeChars[i] - i ) + token.substr( m_escapeChars[i] -i +1 );
-            m_escapeChars.clear();
-            if( startsWith( token, "exclude:" ) ) {
-                m_exclusion = true;
-                token = token.substr( 8 );
-            }
-            if( !token.empty() ) {
-                if (m_exclusion) {
-                    m_currentFilter.m_forbidden.emplace_back(std::make_unique<T>(token, m_substring));
-                } else {
-                    m_currentFilter.m_required.emplace_back(std::make_unique<T>(token, m_substring));
-                }
-            }
-            m_substring.clear();
-            m_patternName.clear();
-            m_exclusion = false;
-            m_mode = None;
-        }
+        // Handles common preprocessing of the pattern for name/tag patterns
+        std::string preprocessPattern();
+        // Adds the current pattern as a test name
+        void addNamePattern();
+        // Adds the current pattern as a tag
+        void addTagPattern();
 
         inline void addCharToPattern(char c) {
             m_substring += c;