convert booleans in summary function to correct representation

str() is going to return titlecased "True" which is not how meson works.
This is misleading, so use the meson-specific format instead.

mesonbuild/interpreter/interpreter.py

@@ -154,9 +154,12 @@ class Summary:
                 raise InterpreterException(f'Summary section {section!r} already have key {k!r}')
             formatted_values = []
             for i in listify(v):
-                if isinstance(i, bool) and bool_yn:
+                if isinstance(i, bool):
+                    if bool_yn:
                         formatted_values.append(mlog.green('YES') if i else mlog.red('NO'))
-                elif isinstance(i, (str, int, bool)):
+                    else:
+                        formatted_values.append('true' if i else 'false')
+                elif isinstance(i, (str, int)):
                     formatted_values.append(str(i))
                 elif isinstance(i, (ExternalProgram, Dependency)):
                     FeatureNew.single_use('dependency or external program in summary', '0.57.0', subproject)

unittests/allplatformstests.py

@@ -3530,7 +3530,7 @@ class AllPlatformTests(BasePlatformTests):
 
                 string : bar
                 integer: 1
-                boolean: True
+                boolean: true
 
             subsub undefined
 
@@ -3539,12 +3539,12 @@ class AllPlatformTests(BasePlatformTests):
             My Project 1.0
 
               Configuration
-                Some boolean   : False
+                Some boolean   : false
-                Another boolean: True
+                Another boolean: true
                 Some string    : Hello World
                 A list         : string
                                  1
-                                 True
+                                 true
                 empty list     :
                 enabled_opt    : enabled
                 A number       : 1