Fix some typos.

docs/usermanual-clusters.xml

@@ -158,7 +158,7 @@
     <para>
       For left-to-right scripts (LTR) and top-to-bottom scripts (TTB),
       HarfBuzz will preserve the monotonic property: client programs
-      are guaranteed that monotonically increasing initial clulster
+      are guaranteed that monotonically increasing initial cluster
       values will be returned as monotonically increasing final
       cluster values.
     </para>
@@ -167,7 +167,7 @@
       the directionality of the buffer itself is reversed for final
       output as a matter of design. Therefore, HarfBuzz inverts the
       monotonic property: client programs are guaranteed that
-      monotonically increasing initial clulster values will be
+      monotonically increasing initial cluster values will be
       returned as monotonically <emphasis>decreasing</emphasis> final
       cluster values.
     </para>

docs/usermanual-fonts-and-faces.xml

@@ -37,7 +37,7 @@
       An <type>hb_face_t</type> represents a <emphasis>face</emphasis>
       in HarfBuzz. This data type is a wrapper around an
       <type>hb_blob_t</type> blob that holds the contents of a binary
-      fotn file. Since HarfBuzz supports TrueType Collections and
+      font file. Since HarfBuzz supports TrueType Collections and
       OpenType Collections (each of which can include multiple
       typefaces), a HarfBuzz face also requires an index number
       specifying which typeface in the file you want to use. Most of

src/hb-ot-math.h

@@ -158,7 +158,7 @@ typedef enum { /*< flags >*/
  * hb_ot_math_glyph_part_t:
  * @glyph: The glyph index of the variant part
  * @start_connector_length: The length of the connector on the starting side of the variant part
- * @end_connection_length: The length of the conector on the ending side of the variant part
+ * @end_connection_length: The length of the connector on the ending side of the variant part
  * @full_advance: The total advance of the part
  * @flags: #hb_ot_math_glyph_part_flags_t flags for the part
  *